Compression systems for batteries

ABSTRACT

Batteries including electrochemical cells, associated components, and arrangements thereof are generally described. In some aspects, batteries with housings that undergo relatively little expansion and contraction even in cases where electrochemical cells in the battery undergo a relatively high degree of expansion and contraction during charging and discharging are provided. Batteries configured to apply relatively high magnitudes and uniform force to electrochemical cells in the battery, while in some cases having high energy densities and a relatively low pack burden, are also provided. In certain aspects, arrangements of electrochemical cells and associated components are generally described. In some aspects, thermally conductive solid articles that can be used for aligning components of the battery are described. In some aspects, thermally insulating and compressible components for battery packs are generally described.

RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Patent Application Ser. No. 62/937,761, filed Nov. 19, 2019,and entitled “Batteries, and Associated Systems and Methods,” and U.S.Provisional Application Ser. No. 62/951,086, filed Dec. 20, 2019, andentitled “Batteries, and Associated Systems and Methods,” each of whichis incorporated herein by reference in its entirety for all purposes.

TECHNICAL FIELD

Batteries including electrochemical cells, associated components, andarrangements thereof are generally described.

BACKGROUND

Batteries typically include cells that undergo electrochemical reactionsto produce electric current. Heat may be produced during cycling of thecell, which may affect the performance of the battery. Applying a forceto at least a portion of an electrochemical cell (e.g., during cyclingof the cell) can improve the performance of the electrochemical cell.Certain embodiments of the present disclosure are directed to inventivearticles, systems, and methods relating to the handling of compressiveforce and heat transfer in batteries.

SUMMARY

Batteries including electrochemical cells, associated components, andarrangements thereof are generally described. In some aspects, batterieswith housings that undergo relatively little expansion and contractioneven in cases where electrochemical cells in the battery undergo arelatively high degree of expansion and contraction during charging anddischarging are provided. Batteries configured to apply relatively highmagnitudes and uniform force to electrochemical cells in the battery,while in some cases having high energy densities and a relatively lowpack burden, are also provided. In certain aspects, arrangements ofelectrochemical cells and associated components are generally described.In some aspects, thermally conductive solid articles that can be usedfor aligning components of the battery are described. In some aspects,thermally insulating and compressible components for battery packs aregenerally described. The subject matter of the present inventioninvolves, in some cases, interrelated products, alternative solutions toa particular problem, and/or a plurality of different uses of one ormore systems and/or articles.

In one aspect, batteries are described. In some embodiments, the batterycomprises a stack comprising a first electrochemical cell and a secondelectrochemical cell, wherein the first electrochemical cell comprises afirst electrochemical active region having a largest lateral dimension,and the second electrochemical cell comprises a second electrochemicalactive region having a largest lateral dimension; and a housing at leastpartially enclosing the stack, the housing comprising a solid platecovering at least a portion of an end of the stack; wherein the housingis configured to apply, via the solid plate and tension in a solidhousing component coupled to the solid plate, during at least one periodof time during charge and/or discharge of the first electrochemical celland/or the second electrochemical cell, an anisotropic force with acomponent normal to a first electrode active surface of the firstelectrochemical cell and/or a second electrode active surface of thesecond electrochemical cell defining a pressure of at least 10 kgf/cm²,the solid housing component comprises a metal, metal alloy, composite,polymeric material, or combination thereof, and a ratio of the largestlateral dimension of the solid plate to the largest lateral dimension ofthe first electrochemical active region and/or a ratio of the largestlateral dimension of the solid plate to the largest lateral dimension ofthe second electrochemical active region is less than or equal to 1.5.

In another aspect, batteries are described. In some embodiments, thebattery comprises a stack comprising a first electrochemical cell and asecond electrochemical cell, wherein the first electrochemical cellcomprises a first electrochemical active region having a largest lateraldimension, and the second electrochemical cell comprises a secondelectrochemical active region having a largest lateral dimension; and ahousing at least partially enclosing the stack, the housing comprising asolid plate covering at least a portion of an end of the stack, whereinthe housing has a largest lateral pressure applying dimension; whereinthe housing is configured to apply, via the solid plate and tension in asolid housing component coupled to the solid plate, during at least oneperiod of time during charge and/or discharge of the firstelectrochemical cell and/or the second electrochemical cell, ananisotropic force with a component normal to a first electrode activesurface of the first electrochemical cell and/or a second electrodeactive surface of the second electrochemical cell defining a pressure ofat least 10 kgf/cm², the solid housing component comprises a metal,metal alloy, composite, polymeric material, or combination thereof, anda ratio of the largest lateral pressure-applying dimension to thelargest lateral dimension of the first electrochemical active regionand/or a ratio of the largest lateral pressure-applying dimension of thesolid plate to the largest lateral dimension of the secondelectrochemical active region is less than or equal to 1.6.

In another aspect, batteries are described. In some embodiments, thebattery comprises a stack comprising a first electrochemical cell and asecond electrochemical cell, the stack having a first end and a secondend; a housing at least partially enclosing the stack, the housingcomprising a solid plate covering at least a portion of the first end ofthe stack, wherein the housing is configured to apply, via the solidplate and tension in a solid housing component coupled to the solidplate, during at least one period of time during charge and/or dischargeof the first electrochemical cell and/or the second electrochemicalcell, an anisotropic force with a component normal to a first electrodeactive surface of the first electrochemical cell and/or a secondelectrode active surface of the second electrochemical cell defining apressure of at least 10 kgf/cm², the solid housing component comprises ametal, metal alloy, composite, polymeric material, or combinationthereof, and no auxiliary fastener spanning from the solid plate towardthe second end of the stack along a side of the stack is in tensionduring application of the anisotropic force.

In another aspect, methods are described. In some embodiments, themethod comprises at least partially charging and/or dischargingelectrochemical cells in a battery, such that the electrochemical cellsundergo a cumulative expansion during the charging and/or discharging ofat least 10%, and an expansion of the battery during the charging and/ordischarging is less than or equal to 0.75%.

In some embodiments, the method comprises at least partially chargingand/or discharging electrochemical cells in a battery, such that theelectrochemical cells undergo a cumulative expansion during the chargingand/or discharging; wherein a ratio of the cumulative expansion of theelectrochemical cells to an expansion of the battery is greater than orequal to the total number of electrochemical cells in the battery.

In some embodiments, the method comprises at least partially chargingand/or discharging electrochemical cells in a battery, such that theelectrochemical cells undergo a cumulative expansion during the chargingand/or discharging of greater than 1 mm, and an expansion of the batteryduring the charging and/or discharging is less than or equal to 1 mm.

In another aspect, batteries are described. In some embodiments, thebattery comprises a housing at least partially enclosing: a firstelectrochemical cell; and a second electrochemical cell; wherein: thehousing has a volume of less than or equal to 15000 cm³, the battery hasa specific energy of greater than or equal to 250 Wh/kg and a volumetricdensity of greater than or equal to 230 Wh/L, and the housing isconfigured to apply, during at least one period of time during chargeand/or discharge of the first electrochemical cell and/or the secondelectrochemical cell, an anisotropic force with a component normal tothe first electrode active surface and the second electrode activesurface defining a pressure of at least 10 kgf/cm². In some embodiments,the battery has a specific energy of greater than or equal to 280 Wh/kgand a volumetric density of greater than or equal to 230 Wh/L.

In some embodiments, the battery comprises a housing at least partiallyenclosing: a first electrochemical cell; and a second electrochemicalcell; wherein: the housing comprises a solid plate comprising layerscomprising carbon fiber, one or more of the layers having a tensilemodulus of at least 120 GPa and a flexural modulus of at least 120 GPaat 25° C., and the housing is configured to apply, during at least oneperiod of time during charge and/or discharge of the firstelectrochemical cell and/or the second electrochemical cell, ananisotropic force with a component normal to the first electrode activesurface and the second electrode active surface defining a pressure ofat least 10 kgf/cm².

In another aspect, a multicomponent stack is described. In someembodiments, the multicomponent stack comprises the following in theorder listed: a first electrochemical cell, a first thermally conductivesolid article portion, a thermally insulating compressible solid articleportion, a second thermally conductive solid article portion; and asecond electrochemical cell.

In another aspect, a stack of electrochemical cells is described. Insome embodiments, the stack of electrochemical cells comprises a firstelectrochemical cell, a second electrochemical cell, a thermallyinsulating compressible solid article portion between the firstelectrochemical cell and the second electrochemical cell, and athermally conductive solid article portion between the firstelectrochemical cell and the thermally insulating compressible solidarticle portion.

In another aspect, batteries are described. In some embodiments, thebattery comprises a first thermally conductive solid article portioncomprising a first alignment feature; a first electrochemical cellcoupled to a non-planarity of the first thermally conductive solidarticle portion, the first electrochemical cell comprising a firstelectrochemical active region; a second thermally conductive solidarticle portion comprising a second alignment feature; and a secondelectrochemical cell coupled to a non-planarity of the second thermallyconductive solid article portion, the second electrochemical cellcomprising a second electrochemical active region; wherein the firstalignment feature and the second alignment feature are located such thatwhen the first alignment feature is substantially aligned with thesecond alignment feature, the first electrochemical active region andthe second electrochemical active region are substantially aligned.

In another aspect, a method is described. In some embodiments, themethod comprises substantially aligning a first feature of a firstthermally conductive solid article portion with a second feature of asecond thermally conductive solid article portion, such that a firstelectrochemical active region of a first electrochemical cell issubstantially aligned with a second electrochemical active region of asecond electrochemical cell; wherein the first electrochemical cell iscoupled to a non-planarity of the first thermally conductive solidarticle portion, and the second electrochemical cell is coupled to anon-planarity of the second thermally conductive solid article portion.

In another aspect, batteries are described. In some embodiments, thebattery comprises a first electrochemical cell; a second electrochemicalcell; and a thermally insulating compressible solid article portionbetween the first electrochemical cell and the second electrochemicalcell; wherein the thermally insulating compressible solid articleportion has an effective thermal conductivity of less than or equal to0.5 W m⁻¹ K⁻¹ in a thickness direction at a temperature of 25° C., and acompression set less than or equal to 15% as determined by a constantforce measurement. In some embodiments, the thermally insulatingcompressible solid article portion has an effective thermal conductivityof less than or equal to 0.5 W m⁻¹ K⁻¹ in a thickness direction at atemperature of 25° C., and a compression set less than or equal to 10%.

In another aspect, batteries are described. In some embodiments, thebattery comprises a first electrochemical cell; a second electrochemicalcell; and a thermally insulating compressible solid article portionbetween the first electrochemical cell and the second electrochemicalcell; wherein the thermally insulating compressible solid articleportion has an effective thermal conductivity of less than or equal to0.5 W m⁻¹ K⁻¹ in a thickness direction at a temperature of 25° C., and acompression set less than or equal to 15% as determined by a constantdisplacement measurement. In some embodiments, the thermally insulatingcompressible solid article portion has an effective thermal conductivityof less than or equal to 0.5 W m⁻¹ K⁻¹ in a thickness direction at atemperature of 25° C., and a compression set less than or equal to 10%.

In another aspect, batteries are described. In some embodiments, thebattery comprises a first electrochemical cell; a second electrochemicalcell; and a thermally insulating compressible solid article portionbetween the first electrochemical cell and the second electrochemicalcell; wherein the thermally insulating compressible solid articleportion has an effective thermal conductivity of less than or equal to0.5 W m⁻¹ K⁻¹ in a thickness direction at a temperature of 25° C. and aresilience of at least 60%, and wherein: at a compressive stress of 12kgf/cm², the percent compression of the thermally insulatingcompressible solid article portion is at least 30%, and at a compressivestress of 40 kgf/cm², the percent compression of the thermallyinsulating compressible solid article portion is at least 80%.

In another aspect, batteries are described. In some embodiments, thebattery comprises a stack comprising a first electrochemical cell and asecond electrochemical cell, the stack having a first end, a second end,and a side; and a housing at least partially enclosing the stack, thehousing comprising a first solid housing component covering at least aportion of the first end of the stack and having a portion along atleast some of the side of the stack; a second solid housing componentcovering at least a portion of the second end of the stack and having aportion along at least some of the side of the stack; and a point ofattachment between the first solid housing component and the secondsolid housing component at a region of overlap between the first solidhousing component and the second solid housing component along the sideof the stack; wherein the housing is configured to apply, during atleast one period of time during charge and/or discharge of the firstelectrochemical cell and/or the second electrochemical cell, ananisotropic force with a component normal to a first electrode activesurface of the first electrochemical cell and/or a second electrodeactive surface of the second electrochemical cell defining a pressure ofat least 10 kgf/cm².

In another aspect, batteries are described. In some embodiments, thebattery comprises a stack comprising a first electrochemical cell and asecond electrochemical cell, the stack having a first end, and a secondend; and a housing at least partially enclosing the stack, the housingcomprising a first solid plate covering at least a portion of the firstend of the stack; a second solid plate covering at least a portion ofthe second end of stack, and a solid housing component; whereinmechanically interlocking features of the discrete solid housingcomponent and a lateral edge of the first solid plate establish a firstjoint, mechanically interlocking features of the discrete solid housingcomponent and a lateral edge of the second solid plate establish asecond joint, and the housing is configured to apply, during at leastone period of time during charge and/or discharge of the firstelectrochemical cell and/or the second electrochemical cell, ananisotropic force with a component normal to a first electrode activesurface of the first electrochemical cell and/or a second electrodeactive surface of the second electrochemical cell defining a pressure ofat least 10 kgf/cm².

In another aspect, batteries are described. In some embodiments, thebattery comprises a stack comprising a first electrochemical cell and asecond electrochemical cell, the stack having a first end, a second end,and a side; and a housing at least partially enclosing the stack, thehousing comprising a first solid housing component covering at least aportion of the first end of the stack and having a portion along atleast some of the side of the stack; and a second solid housingcomponent covering at least a portion of the second end of the stack andhaving a portion along at least some of the side of the stack; wherein:the first solid housing component and the second solid housing componentare mechanically joined by at least one additional solid housingcomponent along the side of the stack and overlapping the first solidhousing component and/or the second housing component, and the housingis configured to apply, during at least one period of time during chargeand/or discharge of the first electrochemical cell and/or the secondelectrochemical cell, an anisotropic force with a component normal to afirst electrode active surface of the first electrochemical cell and/ora second electrode active surface of the second electrochemical celldefining a pressure of at least 10 kgf/cm².

In another aspect, methods are described. In some embodiments, themethod comprises applying an external anisotropic force to a stackcomprising a first electrochemical cell and a second electrochemicalcell, the anisotropic force having a component normal to a firstelectrode active surface of the first electrochemical cell and/or asecond electrode active surface of the second electrochemical celldefining a pressure of at least 10 kgf/cm², wherein a housing at leastpartially encloses the stack; attaching a first solid housing componentof the housing to a second solid housing component during at least aportion of the step of applying the external anisotropic force; andremoving the applied external anisotropic force while maintaining, viatension in the attached first solid housing component and the secondsolid housing component, an anisotropic force having a component normalto the first electrode active surface and/or the second electrode activesurface defining a pressure of at least 10 kgf/cm².

In another aspect, methods are described. In some embodiments, themethod comprises applying an external anisotropic force to a stackcomprising a first electrochemical cell and a second electrochemicalcell, the anisotropic force having a component normal to a firstelectrode active surface of the first electrochemical cell and/or asecond electrode active surface of the second electrochemical celldefining a pressure of at least 10 kgf/cm², wherein a housing at leastpartially encloses the stack; attaching a solid housing component of thehousing to a first solid plate covering at least a portion of a firstend of the stack during at least a portion of the step of applying theexternal anisotropic force, wherein the solid housing component isattached to a second solid plate covering at least a portion of a secondend of the stack during at least a portion of the step of applying theexternal anisotropic force; and removing the applied externalanisotropic force while maintaining, via tension in the attached solidhousing component, an anisotropic force having a component normal to thefirst electrode active surface and/or the second electrode activesurface defining a pressure of at least 10 kgf/cm².

In another aspect, methods are described. In some embodiments, themethod comprises applying an external anisotropic force to a stackcomprising a first electrochemical cell and a second electrochemicalcell, the anisotropic force having a component normal to a firstelectrode active surface of the first electrochemical cell and/or asecond electrode active surface of the second electrochemical celldefining a pressure of at least 10 kgf/cm², wherein a housing at leastpartially encloses the stack; attaching a first solid housing componentof the housing to a second discrete solid housing component during atleast a portion of the step of applying the external anisotropic forceby attaching the first solid housing component to one or more additionalsolid housing components that are attached to the second solid housingcomponent; removing the applied external anisotropic force whilemaintaining, via tension in at least one of the first solid housingcomponent, the second solid housing component, or the one or moreadditional solid housing components, an anisotropic force having acomponent normal to the first electrode active surface and/or the secondelectrode active surface defining a pressure of at least 10 kgf/cm².

Other advantages and novel features of the present invention will becomeapparent from the following detailed description of various non-limitingembodiments of the invention when considered in conjunction with theaccompanying figures. In cases where the present specification and adocument incorporated by reference include conflicting and/orinconsistent disclosure, the present specification shall control.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting embodiments of the present invention will be described byway of example with reference to the accompanying figures, which areschematic and are not intended to be drawn to scale. In the figures,each identical or nearly identical component illustrated is typicallyrepresented by a single numeral. For purposes of clarity, not everycomponent is labeled in every figure, nor is every component of eachembodiment of the invention shown where illustration is not necessary toallow those of ordinary skill in the art to understand the invention. Inthe figures:

FIGS. 1A-1B show cross-sectional schematic diagrams of exemplarybatteries comprising electrochemical cells and an optional housing,according to some embodiments;

FIG. 2 shows a cross-sectional schematic diagram of an exemplaryelectrochemical cell, according to some embodiments;

FIG. 3A shows a cross-sectional schematic diagram of an exemplarybattery and solid plates, according to some embodiments;

FIGS. 3B-3D show exploded view schematic diagrams of solid platescomprising layers of carbon fiber, according to some embodiments;

FIG. 3E shows an angle between the orientation of carbon fibers withinlayers of carbon fiber, according to some embodiments;

FIG. 3F shows an exploded view schematic diagram of a solid platecomprising layers of carbon fiber, according to some embodiments;

FIG. 3G shows angles between the orientation of carbon fibers withinlayers of carbon fiber, according to some embodiments;

FIG. 4 shows a cross-sectional schematic diagram of an exemplary batterycomprising a stack comprising electrochemical cells, and a housing thatcomprises a solid plate and a solid housing component, according to someembodiments;

FIG. 5A shows an exploded perspective schematic diagram of an exemplarybattery comprising a stack comprising electrochemical cells, and ahousing that comprises a solid plate and a solid housing component,according to some embodiments;

FIG. 5B shows a perspective schematic diagram of an exemplary batterycomprising a stack comprising electrochemical cells, and a housing thatcomprises a solid plate and a solid housing component, according to someembodiments;

FIG. 5C shows a perspective schematic diagram of an exemplary batterycomprising a stack comprising electrochemical cells, and a housing thatcomprises a solid plate, a solid housing component, and an electronicscomponent, according to some embodiments;

FIG. 6A shows a side-view schematic diagram of an exemplary batterycomprising a stack comprising electrochemical cells, and a housing thatcomprises a solid plate comprising a recess and a solid housingcomponent comprising a projection, according to some embodiments;

FIG. 6B shows an exploded perspective schematic diagram of an exemplarybattery comprising a stack comprising electrochemical cells, and ahousing that comprises a solid plate comprising a recess and a solidhousing component comprising a projection, according to someembodiments;

FIG. 6C shows a perspective schematic diagram of an exemplary batterycomprising a stack comprising electrochemical cells, and a housing thatcomprises a solid plate comprising a recess and a solid housingcomponent comprising a projection, according to some embodiments;

FIG. 7A shows a cross-sectional schematic diagram of an exemplarybattery comprising a stack comprising electrochemical cells, and ahousing that comprises a solid plate, a solid housing component, and ahousing stop portion, according to some embodiments;

FIG. 7B shows an exploded perspective schematic diagram of an exemplarybattery comprising a stack comprising electrochemical cells, and ahousing that comprises a solid plate, a solid housing component, and ahousing stop portion, according to some embodiments;

FIG. 7C shows a perspective schematic diagram of an exemplary batterycomprising a stack comprising electrochemical cells, and a housing thatcomprises a solid plate, a solid housing component, and a housing stopportion, according to some embodiments;

FIG. 7D shows an exploded perspective schematic diagram of an exemplarybattery comprising a stack comprising electrochemical cells, and ahousing that comprises a solid plate, a solid housing component, and ahousing stop portion, according to some embodiments;

FIG. 7E shows a perspective schematic diagram of an exemplary batterycomprising a stack comprising electrochemical cells, and a housing thatcomprises a solid plate, a solid housing component, and a housing stopportion, according to some embodiments;

FIG. 8A shows a side-view schematic diagram of an exemplary batterycomprising a stack comprising electrochemical cells, and a housing thatcomprises a solid plate and a solid housing component comprising alateral portion, according to some embodiments;

FIG. 8B shows an exploded perspective schematic diagram of an exemplarybattery comprising a stack comprising electrochemical cells, and ahousing that comprises a solid plate and a solid housing componentcomprising a lateral portion, according to some embodiments;

FIG. 8C shows a perspective schematic diagram of an exemplary batterycomprising a stack comprising electrochemical cells, and a housing thatcomprises a solid plate and a solid housing component comprising alateral portion, according to some embodiments;

FIG. 9 shows a cross-sectional schematic diagram of an exemplary batterycomprising a stack comprising electrochemical cells, and a housing thatcomprises solid housing components, according to some embodiments;

FIG. 10 shows a cross-sectional schematic diagram of an exemplarybattery comprising a stack comprising electrochemical cells, and ahousing that comprises a solid housing component joined to solid platesvia mechanically interlocking features, according to some embodiments;

FIG. 11 shows a cross-sectional schematic diagram of an exemplarybattery comprising a stack comprising electrochemical cells, and ahousing that comprises solid housing components, according to someembodiments;

FIG. 12 shows a cross-sectional schematic diagram of an exemplarybattery comprising a stack comprising electrochemical cells, a contouredsolid article portion, and a housing, according to some embodiments;

FIGS. 13A-13B show cross-sectional schematic diagrams of exemplarystacks comprising electrochemical cells, thermally conductive solidarticle portions, and a thermally insulating compressible solid articleportion, according to some embodiments;

FIGS. 14A-14B show cross-sectional schematic diagrams of exemplarystacks comprising electrochemical cells, thermally conductive solidarticle portions, a thermally insulating compressible solid articleportion, and a solid plate in the absence and presence of an anisotropicforce, respectively, according to some embodiments;

FIG. 15 shows a cross-sectional schematic diagram of an exemplary stackcomprising an electrochemical cell, thermally conductive solid articleportion, and a thermally insulating compressible solid article portion,according to some embodiments;

FIG. 16 shows a cross-sectional schematic diagram of an exemplary stackcomprising electrochemical cells, thermally conductive solid articleportions, and thermally insulating compressible solid article portions,according to some embodiments;

FIG. 17 shows a cross-sectional schematic diagram of an exemplarybattery comprising electrochemical cells and thermally conductive solidarticle portions comprising alignment features, according to someembodiments;

FIG. 18 shows a cross-sectional schematic diagram of an exemplaryelectrochemical cell, according to some embodiments;

FIG. 19 shows a perspective view schematic diagram of an exemplarythermally conductive solid article portion comprising an alignmentfeature and a non-planarity, according to some embodiments;

FIG. 20 shows a cross-sectional schematic diagram of an exemplarybattery comprising electrochemical cells and thermally conductive solidarticle portions comprising alignment features, according to someembodiments;

FIG. 21 shows a cross-sectional schematic diagram of an exemplarybattery comprising electrochemical cells, thermally conductive solidarticle portions comprising alignment features, and a thermallyinsulating compressible solid article portion, according to someembodiments;

FIG. 22 shows a cross-sectional schematic diagram of an exemplarybattery comprising electrochemical cells and a thermally insulatingcompressible solid article portion, according to some embodiments;

FIGS. 23A-23B show cross-sectional schematic diagrams of exemplarybatteries comprising electrochemical cells and a thermally insulatingcompressible solid article portion, according to some embodiments;

FIGS. 24A-24B show cross-sectional schematic diagrams of an exemplarybattery comprising electrochemical cells and a thermally insulatingcompressible solid article portion in the absence and presence of ananisotropic force, respectively, according to some embodiments;

FIG. 25 shows a plot of a region of compressive stress versus percentcompression responses for a thermally insulating compressible solidarticle portion, according to some embodiments;

FIG. 26 shows a cross-sectional schematic diagram of an exemplarybattery comprising electrochemical cells and thermally insulatingcompressible solid article portions, according to some embodiments;

FIGS. 27A-27B show perspective schematic illustrations of an exemplarybattery comprising electrochemical cells, according to some embodiments;

FIG. 28 shows a perspective schematic illustration of an exemplarybattery comprising electrochemical cells, thermally conductive solidarticle portions comprising alignment features, and a thermallyinsulating compressible solid article portion, according to someembodiments;

FIGS. 29A-29E show schematic diagrams of components of an exemplarybattery, according to some embodiments;

FIG. 30A shows a schematic illustration of an exemplary apparatus forapplying a force to an electrochemical cell and measuring pressure andchanges in electrochemical cell thickness, according to someembodiments;

FIG. 30B shows a plot of displacement, cell breathing, and dischargecapacity as a function of number of cycles of an exemplary battery,according to some embodiments;

FIG. 31 shows a plot of compressive stress versus percent compressioncurves for thermally insulating compressible solid article portions,according to some embodiments;

FIGS. 32A-32C show schematic illustrations related to exemplary solidplates and related tests for batteries, according to some embodiments;

FIGS. 33A-33B show exploded perspective schematic illustrations ofcarbon fiber layers, according to some embodiments;

FIGS. 34A-34B show schematic illustrations of solid plates, according tosome embodiments;

FIGS. 35A-35B show pressure distributions measured within exemplarybatteries, according to some embodiments;

FIGS. 36A-36B show pressure distributions measured within exemplarybatteries, according to some embodiments;

FIGS. 37A-37B show pressure distributions measured within exemplarybatteries, according to some embodiments;

FIGS. 38A-38B show pressure distributions measured within exemplarybatteries, according to some embodiments;

FIGS. 39A-39B show pressure distributions measured within exemplarybatteries, according to some embodiments;

FIGS. 40A-40B show pressure distributions measured within exemplarybatteries, according to some embodiments;

FIGS. 41A-41B show pressure distributions measured within exemplarybatteries, according to some embodiments;

FIGS. 42A-42B show pressure distributions measured within exemplarybatteries, according to some embodiments;

FIG. 43 shows cross-sectional schematic diagram of a contoured solidarticle portion, according to some embodiments;

FIG. 44A-44B show perspective schematic illustrations of contoured solidarticle portions, according to some embodiments;

FIGS. 45A-45B show pressure distributions measured within exemplarybatteries, according to some embodiments;

FIGS. 46A-46B show pressure measured within exemplary batteries as afunction of the number of charge-discharge cycles, according to someembodiments;

FIGS. 47A-47B show pressure distributions measured within exemplarybatteries, according to some embodiments;

FIGS. 48A-48B show pressure distributions measured within exemplarybatteries, according to some embodiments;

FIGS. 49A-49B show pressure distributions measured within exemplarybatteries, according to some embodiments;

FIG. 50 shows the discharge capacity of batteries as a function of thenumber of charge-discharge cycles, according to some embodiments;

FIG. 51 shows the discharge capacity of exemplary batteries as afunction of the number of charge-discharge cycles, according to someembodiments;

FIGS. 52A-52B show thermally insulating compressible solid articleportions having variable density, according to some embodiments;

FIGS. 53A-53B show schematic diagrams of multi-cell batteries, accordingto some embodiments;

FIG. 54 shows pressure measured within an exemplary battery as afunction of the number of charge-discharge cycles, according to someembodiments;

FIG. 55 shows discharge capacity of an exemplary battery as a functionof the number of charge-discharge cycles, according to some embodiments;

FIG. 56A shows a constant-load creep curve of a thermally insulatingcompressible solid article portion, according to some embodiments; and

FIG. 56B shows a force-relaxation curve of a thermally insulatingcompressible solid article portion, according to some embodiments.

DETAILED DESCRIPTION

Batteries including electrochemical cells, associated components, andarrangements thereof are generally described. In some aspects, batterieswith housings that undergo relatively little expansion and contractioneven in cases where electrochemical cells in the battery undergo arelatively high degree of expansion and contraction during charging anddischarging are provided. Batteries configured to apply relatively highmagnitudes and uniform force to electrochemical cells in the battery,while in some cases having high energy densities and a relatively lowpack burden, are also provided. In certain aspects, arrangements ofelectrochemical cells and associated components are generally described.In some aspects, thermally conductive solid articles that can be usedfor aligning components of the battery are described. In some aspects,thermally insulating and compressible components for battery packs aregenerally described. The present disclosure describes multiple inventiveaspects relating to battery components and arrangements thereof,application of force to multiple electrochemical cells in battery packs,and thermal management. These inventive aspects can, alone or incombination, lead to the manufacture of batteries with unexpectedproperties such as unexpectedly high energy densities and durability.

In some cases, it may be beneficial to apply force to electrochemicalcells in a battery. For example, in some cases applying an anisotropicforce with a component normal to at least one of the electrochemicalcells can improve performance during charging and/or discharging byreducing problems such as dendrite formation and surface roughening ofthe electrode while improving current density. One such example is thecase where at least one of the electrochemical cells of the batterycomprises lithium metal or a lithium metal alloy as an electrode activematerial. Lithium metal may undergo dendrite growth, for example, whichcan in certain cases lead to failure of the electrochemical cell andsafety hazards. Application of relatively high magnitudes of anisotropicforce to electrodes comprising lithium metal may mitigate lithiumdendrite formation and other deleterious phenomena. However, it has beenrealized in the context of the present disclosure that numerouschallenges may emerge when applying force within batteries comprisingmultiple electrochemical cells (e.g., comprising lithium and/or lithiumalloy as an electrode active material). For example, application of arelatively uniform force such that each of the electrochemical cellsexperiences a relatively similar pressure distribution can be importantfor performance and durability, and managing pressure on multiple cellsmust be accomplished simultaneously. Further, certain types ofelectrochemical cells may undergo relatively large dimensional changesduring cycling. As one example, an electrode comprising lithium and/orlithium metal alloy may expand significantly due to lithium depositionduring charging and contract significantly upon lithium ion releaseduring discharging. Such dimensional changes of the electrochemicalcells may lead to uneven pressure distributions and problematic batterypack dimensional changes.

The present disclosure provides methods, articles, and devices that can,in some cases, be used to mitigate such dimensional changes of theoverall battery (e.g., the housing) even in situations whereelectrochemical cells may expand and contract. For example, relativelyhigh magnitudes of force (e.g., defining a pressure of greater than orequal to 10 kgf/cm² and up to 40 kgf/cm²) may be applied. For example,it has been realized that relatively high magnitudes of force may beapplied relatively uniformly using certain housing components (e.g.,solid plates) having relatively high stiffness while being lightweight(e.g., certain types of carbon fiber having certain weaves andthicknesses). Further, certain articles in the battery may compensatefor dimensional changes of the electrochemical cells (e.g., thermallyinsulating compressible solid article portions such as microcellularelastomeric foams). It has been discovered that certain types ofcomponents can have suitable mechanical properties for use in batteriesunder compressive force (e.g., relatively low compression set,relatively high resilience) while being thermally insulating. Some suchthermally insulating compressible solid article portions may then becapable of serving multiple roles: compensating for dimensional changesin electrochemical cells and mitigating heat transfer betweenelectrochemical cells. It has also been discovered that aligningcomponents (e.g., electrochemical active regions of the electrochemicalcells) of the battery can lead to improved performance and durability(e.g., by increasing the uniformity of the pressure distributionexperienced by the electrochemical active regions). Certain aspects ofthe present disclosure are related to thermally conductive solid articleportions that can be used to align electrochemical active regions of thebattery while also performing other functions, such as facilitating heattransfer away from the electrochemical cells (e.g., laterally). The useof articles capable of alignment and thermal transfer may reduce thenumber of components needed for the battery, which may reducecomplexity, pack burden, and/or costs. Certain aspects also relate tounconventional arrangements of components that can simultaneouslymitigate multiple potentially deleterious phenomena associated withbatteries comprising multiple electrochemical cells, while usingrelatively few components, which may allow for relatively high energydensities while also allowing for good durability. For example, certainarrangements of electrochemical cells, thermally conductive solidarticle portions, and thermally insulating compressible solid articleportions may promote unexpectedly efficient heat transfer away from theelectrochemical cells while also facilitating compensation for appliedforces and cell breathing and facilitating relatively uniform pressuredistributions (e.g., within ±2.5 kgf/cm² or within ±2 kgf/cm² across anelectrochemical active region).

In one aspect, batteries are generally described. The battery mayinclude, in some embodiments, one or more rechargeable electrochemicalcells. In some embodiments, the battery comprises one or morerechargeable lithium-ion electrochemical cells.

FIGS. 1A-1B are cross-sectional schematic diagrams of a non-limitingembodiment of battery 100. The battery may comprise one or moreelectrochemical cells as well as one or more other components (e.g.,articles stacked with the electrochemical cells, housings, electricaland thermal management equipment, etc.). In some embodiments, thebattery comprises multiple electrochemical cells, including a firstelectrochemical cell and a second electrochemical cell. For example,battery 100 in FIGS. 1A-1B comprises first electrochemical cell 110 andsecond electrochemical cell 120 at least partially enclosed by optionalhousing 102. The battery may have any of a variety of suitableconfigurations including, but not limited to, a stacked configuration, afolded configuration, or a wound configuration. In some embodiments, atleast one electrochemical cell of the battery (e.g., firstelectrochemical cell, second electrochemical cell) comprises lithiumand/or a lithium metal alloy as an electrode active material.

In some embodiments, electrochemical cells in the battery (e.g., thefirst electrochemical cell, the second electrochemical cell) comprise atleast one anode. FIG. 2 shows a schematic diagram of one exemplaryembodiment of first electrochemical cell 110 comprising anode 112. Insome cases, the anode comprises an anode active material. As usedherein, an “anode active material” refers to any electrochemicallyactive species associated with an anode. In some embodiments, the anodecomprises lithium metal and/or a lithium metal alloy as an anode activematerial. For example, referring again to FIG. 2 , anode 112 compriseslithium metal and/or a lithium metal alloy as an anode active materialin some embodiments. An electrode such as an anode can comprise, inaccordance with certain embodiments, lithium metal and/or a lithiummetal alloy as an electrode active material during at least a portion ofor during all of a charging and/or discharging process of theelectrochemical cell. In certain cases, the anode is or comprisesvapor-deposited lithium (e.g., a vapor-deposited lithium film).Additional suitable anode active materials are described in more detailbelow. Certain embodiments described herein may be directed to systems,devices, and methods that may allow for improved performance (e.g.,magnitude and uniformity of applied force, thermal management, alignmentof electrochemical active regions to promote uniformity of lithiumdeposition during charging) of electrochemical devices comprisingcertain anodes, such as lithium metal-containing anodes.

In some embodiments, electrochemical cells in the battery (e.g., thefirst electrochemical cell, the second electrochemical cell) comprise atleast one cathode. For example, referring again to FIG. 2 , firstelectrochemical cell 110 comprises cathode 114. The cathode can comprisea cathode active material. As used herein, a “cathode active material”refers to any electrochemically active species associated with acathode. In certain cases, the cathode active material may be orcomprise a lithium intercalation compound (e.g., a metal oxide lithiumintercalation compound). As one non-limiting example, in someembodiments, cathode 114 in FIG. 2 comprises a nickel-cobalt-manganeselithium intercalation compound. Suitable cathode materials are describedin more detail below.

As used herein, “cathode” refers to the electrode in which an electrodeactive material is oxidized during charging and reduced duringdischarging, and “anode” refers to the electrode in which an electrodeactive material is reduced during charging and oxidized duringdischarging.

In some embodiments, electrochemical cells in the battery (e.g., thefirst electrochemical cell, the second electrochemical cell) comprise aseparator between the anode and the cathode. FIG. 2 shows exemplaryseparator 115 between anode 112 and cathode 114, according to certainembodiments. The separator may be a solid electronically non-conductiveor insulative material that separates or insulates the anode and thecathode from each other, preventing short circuiting, and that permitsthe transport of ions between the anode and the cathode. In someembodiments, the separator is porous and may be permeable to anelectrolyte.

It should be understood that while in some embodiments the firstelectrochemical cell and the second electrochemical cell have the sametypes of components (e.g., same anode active material, same cathodeactive material, same type of separator), in other embodiments the firstelectrochemical cell has one or more different components than thesecond electrochemical cell (e.g., a different anode active material, adifferent cathode active material, a different type of separator). Insome embodiments, the first electrochemical cell and the secondelectrochemical cell are identical in composition and/or dimensions.

In some embodiments, the battery comprises a housing. The housing may atleast partially enclose other components of the battery. For example,the housing may at least partially enclose the first electrochemicalcell and the second electrochemical cell. FIG. 1A shows optional housing102 at least partially enclosing first electrochemical cell 110 andsecond electrochemical cell 120, according to certain embodiments. Thehousing may comprise rigid components. As one example, the housing maycomprise one or more solid plates. The solid plate may, for example, bean endplate. FIG. 3A shows a cross-sectional schematic diagram ofexemplary battery 100 comprising housing 202, housing 202 comprisingfirst solid plate 201 and second solid plate 203. Further details ofcertain solid plates that may be used in the battery are describedbelow. In certain cases, the housing does not comprise a solid plate.For example, in some cases, the solid surface and other components of acontainment structure configured to house the electrochemical device arepart of a unitary structure.

Some embodiments are related to applying, during at least one period oftime during charge and/or discharge of the electrochemical cells (e.g.,first electrochemical cell, second electrochemical cell), an anisotropicforce with a component normal to an electrode active surface of at leastone electrochemical cell of the battery. As mentioned above, applicationof such a force may reduce potentially deleterious phenomena associatedwith certain types of electrochemical cells (e.g., cells comprisinglithium metal as an electrode active material) and improve utilization.For example, in some cases, applying an anisotropic force with acomponent normal to an active surface of an electrode of theelectrochemical device can reduce problems (such as surface rougheningof the electrode and dendrite formation) while improving currentdensity. Application of such forces to multiple electrochemical cells ofa battery pack may present certain challenges, including uniformity ofpressure distribution for each electrochemical cell, which can beimportant for both performance and durability. Certain aspects describedherein may, in some cases, address and overcome such challenges.

FIG. 1A depicts a schematic cross-sectional illustration of a force thatmay be applied to the first electrochemical cell and the secondelectrochemical cell in the direction of arrow 181. Arrow 182illustrates the component of force 181 that is normal to an activesurface of first electrochemical cell 110, according to certainembodiments.

In some embodiments, the housing of the battery is configured to apply,during at least one period of time during charge and/or discharge of thefirst electrochemical cell and/or the second electrochemical cell, ananisotropic force having a relatively high magnitude component normal toelectrode active surfaces of at least one (or all) of theelectrochemical cells in the battery. For example, in some embodimentswhere the battery comprises a first electrochemical cell having a firstelectrode active surface and a second electrochemical cell having asecond electrode active surface, the housing of the battery isconfigured to apply, during at least one period of time during chargeand/or discharge of the first electrochemical cell and/or the secondelectrochemical cell, an anisotropic force having a relatively highmagnitude component normal to the first electrode active surface and thesecond electrode active surface. The housing may be configured to applysuch a force in a variety of ways. For example, in some embodiments, thehousing comprises two solid articles (e.g., a first solid plate and asecond solid plate as shown in FIG. 3A, where housing 202 comprisesfirst solid plate 201 and second solid plate 203). An object (e.g., amachine screw, a nut, a spring, etc.) may be used to apply the force byapplying pressure to the ends (or regions near the ends) of the housing.In the case of a machine screw, for example, the electrochemical cellsand other components of the battery may be compressed between the plates(e.g., a first solid plate and a second solid plate) upon rotating thescrew. As another example, in some embodiments, one or more wedges maybe displaced between the housing and a fixed surface (e.g., a tabletop,etc.). The force may be applied by driving the wedge between the housing(e.g., between a solid plate of a containment structure of the housing)and the adjacent fixed surface through the application of force on thewedge (e.g., by turning a machine screw).

Some embodiments comprise applying an anisotropic force with a componentnormal to a first electrode active surface of the first electrochemicalcell and/or a second electrode active surface of the secondelectrochemical cell defining a pressure of at least 10 kgf/cm², atleast 12 kgf/cm², at least 20 kgf/cm², at least 25 kgf/cm², or more. Insome such cases, the housing is configured to apply such anisotropicforces. While high magnitudes of anisotropic force with a componentnormal to an electroactive surface can improve performance, too high ofa magnitude of force may cause problems such as damage to certaincomponents of the battery (e.g., the thermally insulating compressiblesolid article portion described below). It has been unexpectedlyobserved, however, that there are ranges of magnitudes of anisotropicforce that can be applied that can, in some cases, achieve desirableperformance of the battery while avoiding such damage. For example, someembodiments comprise applying (e.g., via the housing) during at leastone period of time during charge and/or discharge of the firstelectrochemical cell and/or the second electrochemical cell, ananisotropic force with a component normal to a first electrode activesurface of the first electrochemical cell and/or a second electrodeactive surface of the second electrochemical cell defining a pressure ofless than or equal to 40 kgf/cm², less than or equal to 35 kgf/cm², lessthan or equal to 30 kgf/cm², or less. Combinations of these ranges(e.g., at least 10 kgf/cm² and less than or equal to 40 kgf/cm², or atleast 12 kgf/cm² and less than or equal to 30 kgf/cm²) are possible.

Some embodiments comprise applying a first anisotropic force with acomponent normal to a first electrode active surface of the firstelectrochemical cell and/or a second electrode active surface of thesecond electrochemical cell defining a pressure having a first magnitudeof at least 10 kgf/cm² (e.g., at least 12 kgf/cm²), and then also duringa charge and/or discharge of the battery, applying a second anisotropicforce with a component normal to a first electrode active surface of thefirst electrochemical cell and/or a second electrode active surface ofthe second electrochemical cell defining a pressure having a secondmagnitude that is at least 10 kgf/cm², at least 12 kgf/cm², or higherand less than or equal to 40 kgf/cm², less than or equal to 30 kgf/cm²,or less. In some embodiments, the second magnitude of pressure isgreater than the first magnitude by a factor of at least 1.2, at least1.5, at least 2, at least 2.5, and/or up to 3, or up to 4. The secondmagnitude may be higher than the first magnitude, for example, in someembodiments where the first magnitude of force is applied via thehousing (e.g., a rigid housing) and during a charging and/or dischargeprocess, expansion of one or more components of the battery (e.g., oneor more electrochemical cells) causes the force experienced by theelectrochemical cells to increase. In some embodiments, the firstmagnitude occurs when the electrochemical cells are at a state of charge(SOC) of less than or equal to 10%, less than or equal to 5%, less thanor equal to 2%, less than or equal to 1%, or 0%. In some embodiments,the second magnitude occurs when the electrochemical cells are at astate of charge of greater than or equal to 50%, greater than or equalto 75%, greater than or equal to 90%, greater than or equal to 95%,greater than or equal to 99%, or 100%. Combinations of these ranges arepossible. For example, in some embodiments, the first magnitude occurswhen the electrochemical cells are at a state of charge of less than orequal to 10% and the second magnitude (e.g., that defines a pressurethat is greater than that of the first magnitude by a factor of at least1.2 and up to 4) occurs when the electrochemical cells are at a state ofcharge of greater than or equal to 50%. In one exemplary embodiment, themagnitude of anisotropic force defines a pressure of 12 kgf/cm² at a 0%SOC and 30 kgf/cm² at a 100% SOC.

As mentioned above, in some embodiments, the battery comprises one ormore solid plates. In some such cases, the housing is configured toapply the anisotropic force via a solid plate. The solid plates may be,for example, endplates configured to apply an anisotropic force to theelectrochemical cells (e.g., first electrochemical cell, secondelectrochemical cell). For example, in FIG. 3A, first solid plate 201and second solid plate 203 are endplates. It should be understood thatthe surfaces of a solid plate do not necessarily need to be flat. Forexample, one of the sides of the solid plate may comprise a surface thatis curved (e.g., contoured, convex) in the absence of an applied force.In some embodiments, the solid plate (e.g., an aluminum solid plate) isconvex with respect to the electrochemical cells in the absence of anapplied force, and under at least one magnitude of applied force the endplate may become less convex (e.g., become flat).

The housing may comprise any suitable solid material. In someembodiments, a solid plate is or comprises a metal, metal alloy,composite material, or a combination thereof. In some cases, the metalthat the solid plate is or comprises is a transition metal. For example,in some embodiments, the solid article is or comprises Ti, Cr, Mn, Fe,Co, Ni, Cu, or a combination thereof. In some embodiments, the solidplate is or comprises a non-transition metal. For example, in someembodiments, the solid article is or comprises Al, Zn, or combinationsthereof. Exemplary metal alloys that the solid plate can be or compriseinclude alloys of aluminum, alloys of iron (e.g., stainless steel), orcombinations thereof. Exemplary composite materials that the solid platecan be or comprise include, but are not limited to, reinforcedpolymeric, metallic, or ceramic materials (e.g., fiber-reinforcedcomposite materials), carbon-containing composites, or combinationsthereof.

In some embodiments, a solid plate (e.g., solid plate 201) of thehousing comprises carbon fiber. Carbon fiber may be present in the solidplate in a relatively high amount (e.g., greater than or equal to 50 wt%, greater than or equal to 75 wt %, greater than or equal to 90 wt %,greater than or equal to 95 wt %, greater than or equal to 99 wt %, 100wt %). Carbon fiber can, in some cases, afford relatively high stiffnessand/or strength while having a relatively low mass (e.g., by having arelatively low mass density). It is been discovered, in the context ofthe present disclosure, that certain types of carbon fiber solid platescan allow for the application of relatively high magnitudes ofanisotropic force to the electrochemical cells of the battery withrelatively uniform distributions across multiple of the electrochemicalcells without burdening the battery with too much mass. In someembodiments, the carbon fiber comprises unidirectional carbon fiber. Inother words, in some embodiments, at least one layer (or all layers) ofthe carbon fiber material of the solid plate is unidirectional withinthe layer. While relatively thin and/or twill weave carbon fibermaterials are known, it has been discovered herein that unidirectionalcarbon fiber laminates may afford relatively beneficial properties(e.g., high stiffness and/or strength, low deflection under load). Insome embodiments, the housing comprises a solid plate comprising carbonfiber, the solid plate having a thickness of at least 5 mm, at least 8mm, at least 10 mm, and/or up to 12 mm, up to 15 mm, up to 20 mm, ormore.

In some embodiments, the solid plate comprises multiple layers of carbonfiber (e.g., unidirectional carbon fiber). In some such embodiments, thesolid plate of the housing comprises a first layer comprising carbonfibers substantially parallel to a first direction in the plane of thefirst layer and a second layer comprising carbon fibers substantiallyparallel to a second direction in the plane of the second layer. In someembodiments, two lines in a plane can be substantially parallel if, forexample, the maximum angle defined by the two lines is less than orequal to 10°, less than or equal to 5°, less than or equal to 2°, orless than or equal to 1°. The angle between the first direction and thesecond direction may be an angle θ. In embodiments in which such a layerorientation pattern is repeated, the pattern can be represented as“[0°/θ].” In some embodiments, θ is greater than or equal to (i.e., morepositive than)−90°, greater than or equal to −75°, greater than or equalto −60°, greater than or equal to −45°, greater than or equal to −30°,greater than or equal to −15°, or greater, and/or less than or equal to90°, less than or equal to 75°, less than or equal to 60°, less than orequal to 45°, less than or equal to 30°, less than or equal to 15°, orless. Combinations of these ranges (e.g., 0 greater than or equal to−90° and less than or equal to 90°) are possible. In some embodiments, θhas a non-zero value. In some embodiments, the solid plate comprises athird layer comprising carbon fibers substantially parallel to the firstdirection. In embodiments in which such a layer orientation pattern isrepeated, the pattern can be represented as “[0°/θ/0°].” FIG. 3D showsone such embodiment, where first solid plate 201 comprises first layer211 comprising carbon fibers 218 substantially parallel to firstdirection 204, second layer 212 comprising carbon fibers 218substantially parallel to second direction 206, and third layer 213comprising carbon fibers 218 substantially parallel to first direction204. FIG. 3E shows angle θ between first direction 204 and seconddirection 206 for the embodiment illustrated in FIG. 3D. For example,the solid plate of the housing may comprise, in order: a first layercomprising carbon fibers substantially parallel to a first direction inthe plane of the first layer, a second layer comprising carbon fiberssubstantially parallel to a second direction in the plane of the secondlayer substantially perpendicular (e.g., within 10°, within 5°, within2°, within 1° of perpendicular) to the first direction, and a thirdlayer comprising carbon fibers substantially parallel to the firstdirection. Put a different way, in some embodiments 0 is within 10°,within 5°, within 2°, within 1° of 90°. Each of the individual layersmay have a unidirectional weave. FIG. 3B depicts one such example, wherefirst solid plate 201 comprises first layer 211 comprising carbon fibers218 substantially parallel to first direction 204, second layer 212comprising carbon fibers 218 substantially parallel to second direction206, which is substantially perpendicular to first direction 204, andthird layer 213 comprising carbon fibers 218 substantially parallel tofirst direction 204, according to some embodiments. It is been observedthat, in some cases, carbon fiber materials having such a “[0°/90°/0°]”orientation of layers may have higher strength and/or stiffness thanother types of carbon fiber materials. While FIG. 3B shows an embodimentof solid plate 201 comprising three layers, more layers are possible. Insome embodiments, the solid plate further comprises, in order, a fourthlayer comprising carbon fibers substantially parallel to the seconddirection and a fifth layer comprising carbon fibers parallel to thefirst direction. FIG. 3C shows one such embodiment, where first solidplate 201 comprises first layer 211 comprising carbon fibers 218substantially parallel to first direction 204, second layer 212comprising carbon fibers 218 substantially parallel to second direction206, which is substantially perpendicular to first direction 204, thirdlayer 213 comprising carbon fibers 218 substantially parallel to firstdirection 204, fourth layer 214 comprising carbon fibers 218substantially parallel to second direction 206, and fifth layer 215comprising carbon fibers 218 substantially parallel to first direction204. In some embodiments, the solid plate of the housing comprises atleast 1, at least 2, at least 3, at least 5, at least 10, at least 15,and/or up to 20, up to 25, up to 50, up to 60, up to 75, or more layersof carbon fiber (e.g., layered carbon fiber with oriented fibers) asdescribed herein. Some or all of these layers (e.g., oriented layers)may have certain mechanical properties described below (e.g., modulus).

In some embodiments, the multiple layers of carbon fiber comprise, inorder: a first layer comprising carbon fibers substantially parallel toa first direction in the plane of the first layer, a second layercomprising carbon fibers substantially parallel (e.g. within 10°, within5°, within 2°, within 1° of parallel) to a second direction in the planeof the second layer, a third layer comprising carbon fiberssubstantially parallel to the first direction in the plane of the thirdlayer, a fourth layer comprising carbon fibers substantially parallel(e.g. within 10°, within 5°, within 2°, within 1° of parallel) to athird direction in the fourth layer, and a fifth layer comprising carbonfibers substantially parallel to the first direction in the plane of thefifth layer. The angle between the first direction and the seconddirection may be an angle θ, and the angle between the first directionand the third direction may be an angle cp. In embodiments in which sucha layer orientation pattern is repeated, the pattern can be representedas “[0°/θ/0°/φ/0°].” It should be understood that when notation of thisform is used, the direction of each layer may be within 10° (i.e.,+/−10°) of the direction denoted by the angle value in the notation. Forexample, a layer orientation having repeating units in which the firstlayer is at 0°, the second layer is at θ, the third layer is at 5°, thefourth layer is at φ, and the fifth layer is at −10° would be consideredto have a “[0°/θ/0°/φ/0°]” layer orientation pattern because each layeris within 10° of the value indicated by the notation. Each of theindividual layers may have a unidirectional weave. In some embodiments,θ is greater than or equal to (i.e., more positive than)−90°, greaterthan or equal to −75°, greater than or equal to −60°, greater than orequal to −45°, greater than or equal to −30°, greater than or equal to−15°, or greater, and/or less than or equal to 90°, less than or equalto 75°, less than or equal to 60°, less than or equal to 45°, less thanor equal to 30°, less than or equal to 15°, or less. Combinations ofthese ranges (e.g., 0 greater than or equal to −90° and less than orequal to 90°) are possible. In some embodiments, y is greater than orequal to −90°, greater than or equal to −75°, greater than or equal to−60°, greater than or equal to −45°, greater than or equal to −30°,greater than or equal to −15°, or greater, and/or less than or equal to90°, less than or equal to 75°, less than or equal to 60°, less than orequal to 45°, less than or equal to 30°, less than or equal to 15°, orless. Combinations of the ranges (e.g., φ greater than or equal to −90°and less than or equal to 90°) are possible. In some embodiments, φ hasa nonzero value. In some embodiments, the value of φ is equal to thenegative value of θ (e.g., θ equals 30° and φ equals −30°, or θ equals60° and φ equals)−60°. FIG. 3F shows one such embodiment, where firstsolid plate 201 comprises first layer 211 comprising carbon fibers 218substantially parallel to first direction 204, second layer 212comprising carbon fibers 218 substantially parallel to second direction206, third layer 213 comprising carbon fibers 218 substantially parallelto first direction 204, fourth layer 214 comprising carbon fibers 218substantially parallel to third direction 220, and fifth layer 215comprising carbon fibers 218 substantially parallel to first direction204. FIG. 3F shows angle θ between first direction 204 and seconddirection 206 and angle φ between first direction 204 and thirddirection 220 for the embodiment illustrated in FIG. 3G.

The multiple layers of carbon fiber may include repeating units of thepatterns of layer orientations described above (e.g., repeating units of[0°/θ], [0°/θ/0°], [0°/θ/0°/φ/0°], etc.). It has been observed that somepatterns of unidirectional carbon fiber layers, with certainorientations (e.g., where 0 equals 30° and φ equals −30°, denoted as“[0°/30°/0°/−30/0°]”) can afford properties that are beneficial in somescenarios. For example, it has been observed that solid articles such assolid plates having some such patterns of unidirectional carbon fiberlayers demonstrate less deflection under applied load than otherwiseidentical solid articles such as solid plates lacking such patterns(e.g., solid plates in which the carbon fibers of each layer are allsubstantially parallel).

In some embodiments, the solid plate comprises carbon fiber having arelatively high modulus. For example, in some embodiments the solidplate comprises layers comprising carbon fiber, and one or more of thelayers has a relatively high tensile modulus and a relatively highflexural modulus. In some embodiments, the solid plate comprises layerscomprising carbon fiber, one or more of the layers having a tensilemodulus of at least 120 GPa, at least 150 GPa, at least 200 GPa, atleast 300 GPa, at least 500 GPa or greater, and a flexural modulus of atleast 120 GPa at least 150 GPa, at least 200 GPa, at least 300 GPa, atleast 500 GPa or greater at room temperature (25° C.). In someembodiments, the solid plate comprises layers comprising carbon fiber,one or more of the layers having a tensile modulus of less than or equalto 650 GPa, less than or equal to 600 GPa, less than or equal to 550 GPaor less, and a flexural modulus of less than or equal to 650 GPa, lessthan or equal to 600 GPa, less than or equal to 550 GPa or less at roomtemperature (25° C.). Combinations of the ranges (e.g., a tensilemodulus of at least 120 GPa and less than or equal to 650 GPa and aflexural modulus of at least 120 GPa and less than or equal to 650 GPa)are possible. The tensile modulus of a layer can be measured using ASTMD3039, and the flexural modulus can be measured using ASTM D790. Incertain instances, the solid plate has a relatively large number oflayers satisfying the modulus ranges above. For example, in someembodiments, the solid plate comprises at least 1, at least 2, at least3, at least 5, at least 10, at least 15, and/or up to 20, up to 25, upto 50, up to 60, up to 75, or more layers comprising carbon fiber havinga tensile modulus of at least 120 GPa, at least 150 GPa, at least 200GPa, at least 300 GPa, at least 500 GPa or greater, and a flexuralmodulus of at least 120 GPa at least 150 GPa, at least 200 GPa, at least300 GPa, at least 500 GPa or greater at room temperature (25° C.). Insome embodiments, the solid plate comprises at least 1, at least 2, atleast 3, at least 5, at least 10, at least 15, and/or up to 20, up to25, up to 50, up to 60, up to 75, or more layers comprising carbon fiberhaving a tensile modulus of less than or equal to 650 GPa, less than orequal to 600 GPa, less than or equal to 550 GPa or less, and a flexuralmodulus of less than or equal to 650 GPa, less than or equal to 600 GPa,less than or equal to 550 GPa or less at room temperature (25° C.).

The housing may comprise couplings that can be used to connectcomponents of the housing and/or apply the anisotropic force. Thehousing may comprise, for example, couplings proximate to the ends ofthe housing (e.g., proximate to the ends of the solid plates). FIG. 3Ashows coupling 205 connecting first solid plate 201 and second solidplate 203, according to certain embodiments. In some embodiments, thehousing of the battery has more than one coupling. In certain cases, thehousing includes at least 2 couplings, at least 4 couplings, and/or upto 8 couplings or more. In some embodiments, the coupling comprises afastener. The fastener may span from one end of the housing to another.As one example, coupling 205 in FIG. 3A may be a fastener spanning fromfirst solid plate 201 to second plate 203 of housing 202. Exemplaryfasteners include, but are not limited to, a rod (e.g., a threaded rod,a rod with interlocking features), a bolt, a screw (e.g., a machinescrew), a nail, a rivet, a tie, a clip (e.g., a side clip, a circlip), aband, or combinations thereof. In some cases, applying a force comprisescausing relative motion between one portion of the coupling (e.g., anut) and a fastener of the coupling (e.g., by tightening a nut at aninterface between the fastener and the solid plate or, in cases wherethe fastener comprises a machine screw, by turning the machine screw).

Some embodiments may comprise at least partially charging and/ordischarging electrochemical cells in a battery, such that theelectrochemical cells undergo a cumulative expansion during the chargingand/or discharging. The cumulative expansion of the electrochemicalcells refers to the sum of the changes in thicknesses of theelectrochemical cells themselves, not counting any other components ofthe battery (e.g., foams, sensors, plates, etc.). For example, referringto FIGS. 1A-1B, during the process of at least partially charging and/ordischarging battery 100, first electrochemical cell 110 and secondelectrochemical cell 120 may expand (e.g., in thickness). Such anexpansion may occur due, for example, to the deposition of lithium metalon an anode when lithium metal is used as an anode active material. Insome embodiments, the electrochemical cells undergo the cumulativeexpansion during charging. During the expansion, first electrochemicalcell 110 may expand from thickness 117 in FIG. 1A to thickness 217 inFIG. 1B, and second electrochemical cell 120 may expand from thickness123 in FIG. 1A to thickness 223 in FIG. 1B, according to certainembodiments. The difference between the sum of thickness 117 andthickness 123 and the sum of thickness 217 and thickness 223 would thenbe the cumulative expansion of first electrochemical cell 110 and secondelectrochemical cell 120. Meanwhile, in some, but not necessarily allembodiments, the battery as a whole also undergoes an expansion duringthe charging and/or discharging. For example, battery 100 may expandfrom thickness 103 in FIG. 1A to thickness 107 in FIG. 1B, according tocertain embodiments. In some embodiments, the electrochemical cells ofthe battery may undergo a cumulative expansion that is relatively large,while an expansion of the battery is relatively small. It has beendiscovered that certain inventive aspects of the present disclosure,such as the application of relatively high magnitudes of force tomultiple electrochemical cells, the use of strong and/or stiff housings(e.g., comprising certain carbon fiber plates), and the use ofcompressible components such as the thermally insulating compressiblesolid article portions described below, may afford such a small (or no)expansion of the battery even when the electrochemical cells expand to arelatively large extent.

In some embodiments, the electrochemical cells of the battery undergo acumulative expansion during the charging and/or discharging of at least10%, at least 15%, at least 20%, and/or up to 30% or more, while anexpansion of the battery during the charging and/or discharging is lessthan or equal to 0.75%, less than or equal to 0.5%, less than or equalto 0.1%, and/or as low as 0.05%. In some embodiments, theelectrochemical cells undergo a cumulative expansion during the chargingand/or discharging, wherein a ratio of the cumulative expansion of theelectrochemical cells to an expansion of the battery is greater than orequal to the total number of electrochemical cells in the battery. Forexample a battery comprising 12 electrochemical cells may undergo acumulative expansion of 13 mm, and the battery may undergo an expansionof 0.9 mm, and therefore the ratio of the cumulative expansion of theelectrochemical cells to the expansion of the battery is 13 divided by0.9=14.4, which is greater than the number of electrochemical cells inthe battery (12). In some embodiments, the electrochemical cells undergoa cumulative expansion during the charging and/or discharging of greaterthan 1 mm, greater than or equal to 1.2 mm, greater than or equal to 1.5mm, greater than or equal to 2 mm, greater than or equal to 5 mm,greater than or equal to 10 mm, greater than or equal to 12 mm, and/orup to 20 mm, up to 30 mm, or more, and an expansion of the batteryduring the charging and/or discharging is less than or equal to 1 mm,less than or equal to 0.75 mm, less than or equal to 0.5 mm, and/or aslow as 0.2 mm, as low as 0.1 mm, or less. It should be understood thatin some embodiments, the cumulative expansion of the electrochemicalcells may be in any of the above-mentioned ranges, while the batterydoes not expand at all. For example, in some embodiments, one or morecomponents of the battery (e.g., a compressible component such as athermally insulating compressible solid article portion) may absorb theexpansion by compressing to an equal extent. In some embodiments, duringthe cumulative expansion of the electrochemical cells, eachelectrochemical cell expands by at least 1 mm. In some embodiments, thecumulative expansion of the electrochemical cells is at least 12 mm.

In some embodiments, the battery has a relatively small volume. It isbeen discovered that certain aspects described herein, alone or incombination, such as the solid plates comprising carbon fiber, thethermally insulating compressible solid article portions, and thethermally conductive solid article portions, can allow for relativelyhigh magnitudes of force and/or relatively high energy densities for thebattery, even with a relatively small volume. In some embodiments, thebattery has a volume of less than or equal to 15000 cm³, less than orequal to 13500 cm³, less than or equal to 12000 cm³, less than or equalto 10000 cm³, less than or equal to 8000 cm³, less than or equal to 6750cm³, less than or equal to 6000 cm³, less than or equal to 5000 cm³,and/or as low as 4000 cm³, or lower. As described in more detail below,certain configurations of the housing may provide for an ability toenclose a relatively large amount of electrochemical cell volume and/orapply relatively high force while having a relatively small housingvolume.

In some embodiments, the battery has a relatively high energy density,as described above. In some embodiments, the battery has a specificenergy of greater than or equal to 250 Wh/kg. In some embodiments, thebattery has a specific energy of greater than or equal to 280 Wh/kg,greater than or equal to 290 Wh/kg, greater than or equal to 300 Wh/kg,and/or up to 320 Wh/kg, up to 350 Wh/kg, or more. In some embodiments,the battery has a volumetric density of greater than or equal to 230Wh/L, greater than or equal to 250 Wh/L, greater than or equal to 280Wh/L, and/or up to 300 Wh/L, or higher.

The battery may, surprisingly, have a relatively high energy densityand/or apply a relatively high magnitude of force while having arelatively low pack burden (defined as one minus the mass of theelectrochemical cells of the battery divided by the total mass of thebattery). Expressed as an equation, pack burden=1−(mass of theelectrochemical cells/mass of the battery). In some embodiments, thebattery has a pack burden of less than or equal to 50%, less than orequal to 45%, less than or equal to 40%, less than or equal to 35%, lessthan or equal to 30%, and/or as low as 25%, as low as 20%, or lower.

In some embodiments, the battery includes components configured suchthat the battery (or portions of the battery) has a relatively lowvolume for a given size of electrochemical cells, compared to otherconfigurations. Having a relatively low housing volume while havingrelatively large electrochemical active regions of cells may affordrelatively large volumetric energy densities. Relatively largevolumetric energy densities may be advantageous in certain applicationswhere limited space for batteries is available, but where a large amountof stored energy may be desired, such as certain battery-poweredvehicles. It has been realized that certain existing housings configuredto apply anisotropic forces may have arrangements or operate undermechanisms that require relatively large spatial profiles. For example,housings configured to apply anisotropic forces to electrochemical cellsvia solid plates generally include fasteners spanning between solidplates. Tension in the fasteners may contribute some or all of the forceapplied to the cells within the housings. The battery in FIG. 3A is onesuch example. However, while such configurations may be useful forcertain applications, the use of fasteners for applying tension whenapplying force via solid plates generally requires a relatively largelateral extension of pressure-applying components of the housing pastlateral dimensions of electrochemical active regions of theelectrochemical cells. Such “overhang” of housing components withrespect to the cells may contribute to a large volume of the overallhousing and battery. Certain embodiments herein are directed toapplication of force to electrochemical cells (e.g., the firstelectrochemical cell, the second electrochemical cell) with relativelylow lateral extension of solid plates and/or pressure-applyingcomponents.

In some embodiments, the battery comprises a stack comprisingelectrochemical cells (e.g., the first electrochemical cell, the secondelectrochemical cell). It should be understood that the stack may be amulticomponent stack comprising non-cell components such as thermallyinsulating compressible solid article portions, thermally conductivesolid article portions, and/or sensors. The stack may be at leastpartially enclosed by a housing comprising a solid plate. The solidplate may cover at least a portion (e.g., at least 10%, at least 25%, atleast 50%, at least 75%, at least 90%, at least 95%, or all) of an endof the stack. A portion of a surface (e.g., an end of a stack) of anobject is considered covered by a second object in this context if thereexists a line perpendicular to and extending out of the portion of thesurface and away from a bulk of the object that intersects any of thesecond object. Those of ordinary skill in the art will appreciate thatany stack of components (e.g., cells) includes two ends: the first endcorresponds to the external surface of the first component (e.g., firstcell) that faces away from the bulk of the stack, and the second endcorresponds to the external surface of the last component (e.g., lastcell) that faces away from the bulk of the stack. In the schematiccross-sectional illustration in FIG. 4 , battery 100 comprises housing302 comprising solid plate 310, where housing 302 at least partiallyencloses stack 304 comprising first electrochemical cell 110 and secondelectrochemical cell 120, in accordance with some embodiments. Stack 304has first end 306 corresponding to the external surface of firstelectrochemical cell 110 that faces away from the bulk of stack 304, andstack 304 also has second end 308 corresponding to the external surfaceof second electrochemical cell 120 that faces away from the bulk ofstack 304, according to certain embodiments. In FIG. 4 , solid plate 310covers at least a portion of first end 306 of stack 304, because line309 perpendicular to and extending out of first end 306 and away fromthe bulk of stack 304 intersects plate 310.

In some embodiments, the housing of the battery further comprises asolid housing component coupled to the solid plate. In some embodiments,the solid housing component is a discrete object separate from the solidplate rather than part of a unitary object with the solid plate (thoughin some embodiments the solid housing component and the solid plate arepart of a unitary solid object). The solid housing component (e.g.,discrete solid housing component) may contribute, at least in part, toapplication of anisotropic force by the housing (e.g., to anelectrochemical cell in the stack). For example, in some embodiments,the housing is configured to apply, via the solid plate and tension inthe solid housing component coupled to the solid plate, during at leastone period of time during charge and/or discharge of the firstelectrochemical cell and/or the second electrochemical cell, ananisotropic force with a component normal to a first electrode activesurface of the first electrochemical cell and/or a second electrodeactive surface of the second electrochemical cell. As noted above, theanisotropic force may define a pressure of at least 10 kgf/cm², at least12 kgf/cm², at least 20 kgf/cm², at least 25 kgf/cm² and/or up to 30kgf/cm², up to 35 kgf/cm², up to 40 kgf/cm², or more. The solid housingcomponent (e.g., discrete solid housing component) may contribute toforce application by being coupled to a first solid plate (covering atleast a portion of a first end of the stack) and a second component ofthe housing covering at least a portion of a second end of the stack(e.g., a second solid plate or a part of a frame). For example,referring again to FIG. 4 , housing 302 comprises solid housingcomponent 314 coupled to first solid plate 310 and second solid plate312 (which covers second end 308 of stack 304). Tension in solid housingcomponent 314 may contribute force causing first solid plate and/orsecond solid plate 312 to compress stack 304, thereby applying ananisotropic force in direction of arrow 182 having component 182 normalto a first electrode active surface of first electrochemical cell 110and/or a second electrode active surface of second electrochemical cell120.

The solid plate may have a largest lateral dimension that is relativelysmall with respect to an electrochemical active region of one or more ofthe electrochemical cells in the battery. Electrochemical active regionsof electrochemical cells are described in more detail below inconnection with FIG. 18 . Having a relatively small lateral profile ofthe solid plate may stand in contrast to solid plates in certainexisting housings having larger lateral profiles (e.g., due to lateralspace needed for load-applying fasteners to pass through the solidplate). Certain embodiments of this disclosure are directed to varioustechniques and configurations that can make inclusion of solid plateshaving relatively small lateral profiles practical (e.g., via certainconfigurations of solid housing components). Small solid plates(relative to the electrochemical cells) may afford overall batterieshaving relatively small volumes, which can be advantageous in someapplications. A lateral dimension of a solid plate refers to a dimensionparallel to an exterior lateral surface of the solid plate (as opposedto a thickness of the solid plate). FIG. 4 shows lateral dimension 326of solid plate 310 as an illustrative example. FIG. 4 also shows firstelectrochemical active region 160 of first electrochemical cell 110 andsecond electrochemical active region 162 of second electrochemical cell120, according to some embodiments. FIGS. 5A-5B show exploded view (FIG.5A) and perspective (FIG. 5B) schematic illustrations of battery 100including housing 302 at least partially enclosing first electrochemicalcell 110 and second electrochemical cell 120, in accordance with someembodiments. In FIGS. 5A-5B, housing 302 comprises solid plate 310having largest lateral dimension 328, as illustrated by the dashed linewith arrows. Solid plate 310 may be a first solid plate, and housing 302may further comprise second solid plate 312 coupled to first solid platevia solid housing component 314.

In some embodiments in which the stack comprises a first electrochemicalcell comprising a first electrochemical active region and a secondelectrochemical cell comprising a second electrochemical active region,a ratio of the largest lateral dimension of the solid plate to thelargest lateral dimension of the first electrochemical active regionand/or a ratio of the largest lateral dimension of the solid plate tothe largest lateral dimension of the second electrochemical activeregion is less than or equal to 1.5, less than or equal to 1.4, lessthan or equal to 1.3, less than or equal to 1.2, less than or equal to1.1, less than or equal to 1.05, less than or equal to 1.02, less thanor equal to 1.01, and/or as low as 1.005, as low as 1.001, or as low as1.

The housing of the battery may have a largest lateral pressure-applyingdimension. A lateral pressure-applying dimension refers to a dimensionof the housing parallel with the lateral exterior surfaces of componentsof the stack and the solid plate that corresponds to components of thehousing under tension such that they participate in the application ofpressure to the electrochemical cells of the stack via the anisotropicforce discussed above.

FIG. 5C illustrates the concept of a lateral pressure-applying dimensionof a housing. Battery 100 comprises housing 302 comprising solid plate310, solid housing component 314, and electronics component 332 coupledto solid plate 310 and positioned along a side of stack 304. Housing 302has largest lateral pressure-applying dimension 328 between far cornersof solid plate 310. (While this matches the largest lateral dimension ofsolid plate 310 in the pictured embodiment, such an occurrence is notnecessary, as in other embodiments parts beyond the solid plate may bepressure-applying and contribute to a largest lateral pressure-applyingdimension). All components of housing 302 within largest lateralpressure-applying dimension 302 are under tension during application offorce by the housing to first electrochemical cell 110 and/or secondelectrochemical cell 120. Housing 302 also has an overall largestlateral dimension 330 from a corner of solid plate 310 to a far cornerof electronics component 332. However, because in this embodimenthousing 302 is configured to apply the anisotropic force via solid plate310 and tension in solid housing component 314, electronics component332 is not under tension and consequently does not substantiallycontribute to the application of pressure to first electrochemical cell110 and/or second electrochemical cell 120. Electronics component 332would therefore not be considered part of a lateral pressure-applyingdimension of housing 302. As a result, part 338 of overall largestlateral dimension 330 is not pressure-applying, and overall largestlateral dimension 330 is larger than the largest lateralpressure-applying dimension 328 of housing 302.

The housing may have a largest lateral pressure-applying dimension thatis relatively small with respect to an electrochemical active region ofone or more of the electrochemical cells in the battery. Having arelatively small lateral pressure-applying profile of the housing maystand in contrast to certain existing pressure-applying housings havinglarger lateral pressure-applying profiles (e.g., due to lateral spaceneeded for load-applying fasteners to pass through one or morecomponents of the housing such as a solid plate). Certain embodiments ofthis disclosure are directed to various techniques and configurationsthat can make housings having relatively small lateral pressure-applyingprofiles practical (e.g., via certain configurations of solid housingcomponents). Small pressure-applying regions of housings (relative tothe electrochemical cells) may afford overall batteries havingrelatively small volumes, which can be advantageous in someapplications.

In some embodiments in which the stack comprises a first electrochemicalcell comprising a first electrochemical active region and a secondelectrochemical cell comprising a second electrochemical active region,a ratio of the largest lateral pressure-applying dimension to thelargest lateral dimension of the first electrochemical active regionand/or a ratio of the largest lateral pressure-applying dimension of thesolid plate to the largest lateral dimension of the secondelectrochemical active region is less than or equal to 1.6, less than orequal to 1.5, less than or equal to 1.4, less than or equal to 1.3, lessthan or equal to 1.2, less than or equal to 1.1, less than or equal to1.05, less than or equal to 1.02, less than or equal to 1.01, and/or aslow as 1.005, as low as 1.001, or as low as 1. In some embodiments, atleast 90%, at least 95%, at least 99%, or all of the firstelectrochemical active region of the first electrochemical cell and/orthe second electrochemical active region of the second electrochemicalcell is covered by a portion of the housing within the largest lateralpressure-applying dimension of the housing.

The solid housing component may couple (or contribute to coupling of)the solid plate covering at least a portion of a first end of the stackto a component of the housing covering at least a portion of second endof the stack. Such a coupling via the solid housing component (e.g.,solid housing component 314) may contribute to the anisotropic forceapplied by the housing. In some embodiments, the solid housing componentspans from the solid plate to the second end of the stack. For example,in FIG. 4 , solid housing component 314 spans from first solid plate tosecond end 308 of stack 304. It should be understood that an objectspanning from a first element to a second element may extend past someor all of either the first element of the second element, provided thatit reach at least a portion of each the two elements in the direction ofthe spanning. For example, in FIG. 4 , solid housing component 314,which reaches all of but does not extend past solid plate 310 andextends past second end 308, is considered to span from solid plate 310to second end 308. In some embodiments in which the housing comprises afirst solid plate covering at least a portion of the first end of thestack and a second solid plate covering at least a portion of the secondend of the stack (e.g., as shown in FIG. 4 ), the solid housingcomponent spans from the first solid plate to the second solid plate.

Solid housing components may join two or more parts of the housing viaany of a variety of coupling techniques. The solid housing componentsmay be part of the underlying structure of the housing. For example, insome embodiments, the housing comprises a frame at least partiallyenclosing the stack, and a solid housing component is a part of theframe (e.g., a side of the frame joining two ends of the frame). Thehousing may have a single solid housing component, or the housing maycomprise multiple solid housing components. In some embodiments, thehousing comprises a first solid housing component along a first side ofthe stack and a second solid housing component on along a second (e.g.,opposite) side of the stack. Housing 302 in FIG. 4 shows one suchembodiment, where first solid housing component 314 and optional secondsolid housing component 316 are along opposite sides of stack 304.

In some embodiments, no auxiliary fastener spanning from the solid platetoward the second end of the stack along a side of the stack is intension during application of the anisotropic force. An auxiliaryfastener in this context is a fastener that is not part of theunderlying housing structure. For example, in FIG. 3A, where housing 202comprises first solid plate 201 coupled to second solid plate 203 via afastener in the form of rod 205, rod 205 is not part of the underlyingstructure of housing 202 and is therefore considered an auxiliaryfastener. In contrast, in FIG. 4 , housing 302 comprises first solidplate 310 and second solid plate 312 coupled via solid housing component314, which is part of an underlying structure of housing 302 and istherefore not considered an auxiliary fastener. A housing in which noauxiliary fastener spans from the solid plate toward the second end ofthe stack along a side of the stack is in tension during application ofthe anisotropic force may still be able to apply the anisotropic forceto the electrochemical cells of the stack even without tension from anauxiliary fastener at least because of the presence of a solid housingcomponent in tension coupled to the solid plate, as described above andbelow. By not requiring an auxiliary fastener in tension for applicationof the anisotropic force, the housing may require less lateral extension(“overhang”) of pressure-applying components such as solid platescompared to housings that employ auxiliary fasteners in tension forforce application. As discussed, less lateral extension beyondelectrochemical active areas of the electrochemical cell may contributeto lower overall housing and battery volumes (and higher volumetricenergy density). In some embodiments, no auxiliary fastener spans fromthe solid plate to the second end of the stack. For example, in FIG. 4 ,no auxiliary fastener spans from solid plate 310 to second end 308 ofstack 304, in accordance with some embodiments. In some embodiments, noauxiliary fastener passes through a thickness of the solid plate. Itshould be understood that while in some embodiments no auxiliaryfastener spans from the solid plate to the second end of the stack (orpasses through a thickness of the solid plate), other fasteners may bepresent in the housing. For example, in some embodiments, fastenerscouple the solid housing component to the solid plate or a solid portionadjacent to the solid plate, as described in more detail below.

The solid housing component may be made of any of a variety ofmaterials, depending on desired properties of the solid housingcomponent and/or the overall battery. The solid housing component may bemade of any of the materials described above for the solid plate. Insome embodiments, the solid housing component comprises a metal (e.g.,aluminum, titanium, etc.), metal alloy (e.g., stainless steel),composite, polymeric material (e.g., a rigid plastic), or combinationthereof. For example, some (e.g., at least 50 wt %, at least 75 wt %, atleast 90 wt %, at least 95 wt %, at least 99 wt %) or all of the solidhousing component may be metal, metal alloy, polymeric material,composite, or a combination thereof. In some embodiments, the solidhousing component comprises a composite material. Exemplary compositematerials that the solid housing component can be or comprise include,but are not limited to, reinforced polymeric, metallic, or ceramicmaterials (e.g., fiber-reinforced composite materials),carbon-containing composites, or combinations thereof. For example, insome embodiments, the solid housing component comprises carbon fiber. Asdescribed above in the context of the solid plate, the solid housingcomponent may comprise multiple layers of carbon fiber (e.g.,unidirectional carbon fiber weaves, optionally with binder). In someembodiments, the solid housing component comprises multiple layers ofcarbon fiber (e.g., unidirectional carbon fiber) having any of theorientation patterns described above (e.g., a “[0°/90°/0°]” pattern, a“[0°/30°/0°/−30/0°]” pattern, etc.). In some embodiments, the solidhousing component comprises a woven fabric. For example, the solidhousing component may comprise multiple layers of woven fabric (e.g.,woven carbon fibers). It has been observed that carbon fiber compositesolid housing components may afford sufficient strength and rigidity forcontributing to application of anisotropic force to cells in the stackwhile being relatively light-weight, which may promote desirablespecific energy densities for certain applications. In some embodimentswhere a housing comprises a solid plate and a solid housing componentcoupled to the solid plate, the solid plate and the solid housingcomponent have the same composition. For example, both may be made ofthe same metal or metal alloy (e.g., aluminum), polymeric material,composite (e.g., carbon fiber composite), or combination thereof.However, in some embodiments the solid plate and the solid housingcomponent are made of different compositions (e.g., different types ofmaterials or the same materials in different relative amounts).

In some embodiments, the solid housing component comprises a material(e.g., a composite comprising carbon fiber) having a relatively highmodulus. In some embodiments, the solid housing component has arelatively high tensile modulus and a relatively high flexural modulus.In some embodiments, some or all of the solid housing component has atensile modulus of at least 1 GPa, at least 5 GPa, at least 10 GPa, atleast 20 GPa, at least 50 GPa, at least 75 GPa, at least 100 GPa, 120GPa, at least 150 GPa, at least 200 GPa, at least 300 GPa, at least 500GPa and/or up to 550 GPa, up to 600 GPa, up to 650 GPa, or greater, anda flexural modulus of at least 120 GPa at least 150 GPa, at least 200GPa, at least 300 GPa, at least 500 GPa and/or up to 550 GPa, up to 600GPa, up to 650 GPa, or greater at room temperature (25° C.). Forexample, in some embodiments the solid housing component compriseslayers comprising a material (e.g., a composite comprising carbonfiber), and one or more of the layers has a relatively high tensilemodulus and a relatively high flexural modulus. In some embodiments, thesolid housing component comprises layers comprising a material (e.g., acomposite comprising carbon fiber), one or more of the layers having atensile modulus of at least 120 GPa, at least 150 GPa, at least 200 GPa,at least 300 GPa, at least 500 GPa or greater, and a flexural modulus ofat least 120 GPa at least 150 GPa, at least 200 GPa, at least 300 GPa,at least 500 GPa or greater at room temperature (25° C.). In someembodiments, the solid housing component comprises layers comprising amaterial (e.g., a composite comprising carbon fiber), one or more of thelayers having a tensile modulus of less than or equal to 650 GPa, lessthan or equal to 600 GPa, less than or equal to 550 GPa or less, and aflexural modulus of less than or equal to 650 GPa, less than or equal to600 GPa, less than or equal to 550 GPa or less at room temperature (25°C.). Combinations of the ranges (e.g., a tensile modulus of at least 120GPa and less than or equal to 650 GPa and a flexural modulus of at least120 GPa and less than or equal to 650 GPa) are possible. In certaininstances, the solid housing component has a relatively large number oflayers satisfying the modulus ranges above. For example, in someembodiments, the solid housing component comprises at least 1, at least2, at least 3, at least 5, at least 10, at least 15, and/or up to 20, upto 25, up to 50, up to 60, up to 75, or more layers comprising amaterial (e.g., a composite comprising carbon fiber) having a tensilemodulus of at least 120 GPa, at least 150 GPa, at least 200 GPa, atleast 300 GPa, at least 500 GPa or greater, and a flexural modulus of atleast 120 GPa at least 150 GPa, at least 200 GPa, at least 300 GPa, atleast 500 GPa or greater at room temperature (25° C.). In someembodiments, the solid housing component comprises at least 1, at least2, at least 3, at least 5, at least 10, at least 15, and/or up to 20, upto 25, up to 50, up to 60, up to 75, or more layers comprising amaterial (e.g., a composite comprising carbon fiber) having a tensilemodulus of less than or equal to 650 GPa, less than or equal to 600 GPa,less than or equal to 550 GPa or less, and a flexural modulus of lessthan or equal to 650 GPa, less than or equal to 600 GPa, less than orequal to 550 GPa or less at room temperature (25° C.).

In some embodiments, a substantial portion of the housing comprises amaterial (e.g., a composite comprising carbon fiber) having a relativelyhigh modulus. In some embodiments, a material having a flexural and/ortensile modulus of at least 120 GPa, at least 150 GPa, at least 200 GPa,at least 300 GPa, at least 500 GPa, and/or up to 550 GPa, up to 600 GPa,up to 650 GPa, or higher is present in the housing in an amount of atleast 50 wt %, at least 75 wt %, at least 90 wt %, at least 95 wt %, ormore. Some embodiments where the housing comprises a material having arelatively high modulus may be advantageous because they facilitatebatteries with a relatively small lateral profile, a relatively highvolumetric energy density, and/or adequate resistance to deformation(e.g., upon application of force). In some embodiments where the housingcomprises a solid plate and a solid housing component, each comprising acomposite material having a relatively high modulus, such as a compositecomprising carbon fiber, it can be beneficial to have some housingcomponents with planarity parallel to a first plane and other housingcomponents with planarity not parallel to that first plane. For example,in some embodiments it may be advantageous for a solid plate of thehousing to have multiple layers of unidirectional carbon fiber havingplanarity parallel to a plane of the solid plate, as well as a solidhousing component (e.g., a frame component spanning from the solid plateto a second end of the stack) having multiple layers of unidirectionalcarbon fiber with planarity nonparallel to (e.g., substantiallyperpendicular to) the plane of the solid plate.

While in some embodiments the solid housing component has a relativelyhigh modulus, such a property is not necessary in all embodiments. Insome embodiments, the solid housing component has a tensile strengthsufficient to avoid observable deflection and/or failure when thehousing applies the anisotropic force to the electrochemical cells. Insome embodiments, the solid housing component has a tensile strength inat least one dimension of at least 10 MPa, at least 20 MPa, at least 50MPa, at least 100 MPa, at least 200 MPa, at least 500 MPa, at least 1GPa, at least 2 GPa, at least 5 GPa, and/or up to 10 GPa, up to 20 GPa,up to 50 GPa, up to 100 GPa, up to 120 GPa, or higher.

In some embodiments, components of the housing of the battery arereinforced by local increases in thickness and/or the attachment ofmechanical doublers. In some embodiments, local increases in thicknessand/or the attachment of mechanical doublers provide additional supportfor portions of the housing (e.g., solid housing components along a sideof the stack) that are pressure-applying or are otherwise mechanicallyloaded under at least some configurations of the housing. In someembodiments, local increases in thickness and/or the attachment ofmechanical doublers facilitate a reduction in the largest lateralpressure applying dimension of the housing and/or increase thegravimetric and/or volumetric energy density of the battery. A localincrease in thickness or a mechanical doubler may have an area of lessthan 100%, less than or equal to 90%, less than or equal to 75%, lessthan or equal to 50%, less than or equal to 25%, less than or equal to10%, less than or equal to 5%, or less of a corresponding solid housingcomponent. Further, a thickness of the solid housing component at alocal increase in thickness and/or a combined thickness of a solidhousing component and a mechanical doubler may be greater than anaverage thickness of the solid housing component by a factor of greaterthan or equal to 1.05, greater than or equal to 1.1, greater than orequal to 1.25, greater than or equal to 1.5, greater than or equal to 2,and/or up to 3, up to 5, or greater. FIGS. 7D-7E introduce an exemplaryembodiment of battery 100, where mechanical doubler 315 is attached tosolid housing component 314. FIG. 7D presents an exploded perspectiveschematic diagram of the battery, while FIG. 7E presents a perspectiveschematic diagram of the battery. Note that while any feature appearingin FIGS. 7D-7E may appear in some embodiments, some embodiments caninclude fewer than all pictured features while still accomplishing anyof a variety of the advantages and performances described above.

The solid housing component may have any of a variety of lengths whilemaintaining rigidity. In some embodiments, such a rigidity even atrelatively long lengths (unlike traditional auxiliary fasteners) affordsan ability for the ratio of the distance between a solid plate and thesecond end of the stack to the largest lateral dimension of the housingto be relatively large if desired. In turn, such a large ratio may allowfor a relatively large number (e.g., at least 6, at least 12, or more)of electrochemical cells to be included in the stack of the battery.Such an ability for relatively long housing components spanning thestack stands in contrast to traditional auxiliary fasteners such as rodsor bolts with nuts. Tension in long fasteners may produce bendingmoments that result in deleterious deflection. Solid housing components(e.g., comprising composites comprising carbon fiber) may notappreciably deflect under such tension. In some embodiments, the ratioof the distance between a solid plate and the second end of the stack tothe largest lateral dimension of the battery is less than or equal to20, less than or equal to 10, less than or equal to 5, less than orequal to 2, less than or equal to 1.5, less than or equal to 1, lessthan or equal to 0.5, less than or equal to 0.2, less than or equal to0.1, or less. In some embodiments, the ratio of the distance between asolid plate and the second end of the stack to the largest lateraldimension of the battery is greater than or equal to 0.01, greater thanor equal to 0.1, greater than or equal to 0.5, greater than or equal 1,greater than or equal to 2, greater than or equal to 5, or greater.Combinations of the above ranges are possible: for instance, in someembodiments, the ratio of the distance between a solid plate and thesecond end of the stack to the largest lateral dimension of the batteryis greater than or equal to 0.01 and less than or equal to 20.

In some embodiments, housings with any given ratio of the distancebetween a solid plate and the second end of the stack to the largestlateral dimension of the housing can be reconfigured to have a new ratioof the distance between the solid plate and the second end of the stackto largest lateral dimension of the battery by modifying and/oradjusting one or more solid housing components of the housing. For agiven collection of geometries, a variety of solid housing componentsfor spanning along a side of the stack of the battery can beinterchanged to accommodate a variety of ratios of the distance betweena solid plate and the second end of the stack to the largest lateralpressure-applying dimension, in some embodiments. In some embodiments,the ability to reconfigure the length of the housing without theadjustment of auxiliary fasteners can facilitate a reduction in thelargest lateral pressure applying dimension of the battery. In someembodiments, the ability to reconfigure the length of the housing insuch a way advantageously reduces the number of parts of the housing.

In some embodiments, the housing comprises a lateral base portionproximate to and/or along a lateral edge of the solid plate. In someembodiments, the lateral base portion is part of the solid plate.However, in some embodiments, the lateral base portion is part of asolid housing component coupled to the solid plate. In some embodiments,batteries can be mounted to an external surface using fasteners (e.g.,auxiliary fasteners). In some embodiments, the lateral base portion isconfigured for mounting the battery to an external surface. Forbatteries that lack a lateral base portion, additional portions of thesolid plate may be required to mount the battery to an external surface,and these may increase the lateral profile of the battery. Therefore,inclusion of a lateral base portion may be advantageous for reducing themaximum lateral pressure-applying dimension of the housing and/orincreasing the battery's volumetric energy density. For example, battery100 in FIGS. 7D-7E includes lateral base portion 319 of housing 302,which may be mounted to an external surface via fasteners 317.

In some embodiments, a relatively large percentage of the stack of thebattery is covered by the housing of the battery. This may, in somecases, be advantageous because it can afford substantial protection tothe battery (e.g., from impact during handling and/or use). In someembodiments, the housing covers at least 30%, at least 50%, at least70%, at least 90%, at least 95%, at least 99%, or 100% of an externalsurface area of the stack.

The solid housing component may couple to the solid plate of the housingin any of a variety of suitable ways. It has been realized that certaincoupling techniques may establish coupling while maintaining relativelysmall lateral profiles for the housing. In some embodiments,mechanically interlocking features of the solid housing component and alateral edge of the solid plate establish a joint. Any of a variety ofsuitable joints may be employed via the interlocking features. Forexample, any of a variety of woodworking joints may be suitable. Itshould be understood that woodworking joints refer to the geometries andbalances of forces associated with the joints, and it is not requiredthat any part of two components joined with a woodworking joint actuallybe made of wood. Examples of types of joints that may be established byinterlocking features of the solid housing component and a lateral edgeof the solid plate include, but are not limited to, box joints, dovetailjoints, splice joints (e.g. tabled splice joints), and Knapp joints.

In some embodiments, a joint between the solid housing components andthe solid plate of the housing is formed at least in part between aprojection of the solid housing component (or solid plate) and a recessof the solid plate (or solid housing component). Some such embodimentsmay involve the solid housing comprising a projection, the solid platecomprising a recess, and the solid housing component and the solid platebeing configured to form a joint at least in part via coupling of theprojection and the recess. For example, referring to FIGS. 6A-6C,exemplary battery 100 may be configured such that first solid housingcomponent 314 has first projection 340 and optional second projection342, while optional second solid housing component 316 has thirdprojection 344 and fourth projection 346. First projection 340 of firstsolid housing component 314 is configured to couple, at least in part,with first recess 350 of solid plate 310 to form a joint, while optionalsecond projection 342 of first solid housing component 314 is configuredto couple, at least in part, with optional second recess 352 of optionalsecond solid plate 312 to form a joint. Third projection 344 of optionalsecond solid housing component 316 is configured to couple, at least inpart, with optional third recess 354 of solid plate 310 to form a joint,while the fourth projection 346 of optional second solid housingcomponent 316 is configured to couple, at least in part, with optionalfourth recess 356 of optional second solid plate 312 to form a joint. Ahousing of this type may, in some embodiments, decrease a largestlateral pressure-applying dimension of the housing relative to a housingcomprising, for example, auxiliary fasteners coupling solid plates.Additionally, use of mechanically interlocking features (e.g., forwoodworking joints) for coupling may require a lower part count thanhousings that employ auxiliary fasteners (e.g., nuts and bolts) forcoupling. In some embodiments, the solid housing component and the solidplate are configured to be joined via a dovetail joint (e.g., viatapered projects and/or recesses in the solid housing component andsolid plate). For example, the solid housing component may comprise maledovetail features at an end of the solid housing component, and thesolid plate may comprise a female dovetail feature (e.g., proximate to alateral edge of the solid plate). The male and female features may mateto form a joint.

FIG. 6A shows a side view schematic illustration of exemplary battery100, where all recesses are identical and where all projections areidentical, in accordance with some embodiments. FIG. 6B shows anexploded schematic illustration of exemplary battery 100 of this type,also revealing optional third solid housing component 318 and optionalfourth solid housing component 320. FIG. 6C shows a perspectiveschematic illustration of exemplary battery 100. It should be understoodthat other embodiments where projections differ from one another arealso contemplated, as are embodiments with more or fewer solid housingcomponents. In some embodiments, the solid housing component comprisesrecesses which can couple, at least in part, with projections of thesolid plates to form joints. In some embodiments in which a solidhousing component and a solid plate are coupled via interlockingmechanical features (e.g., via a woodworking joint), the solid housingcomponent and the solid plate may further be coupled via, for example,an adhesive and/or a weld (e.g., at a joint formed by the interlockingfeatures).

In some embodiments, the solid housing component is coupled to the solidplate via coupling to a housing stop portion adjacent to an exteriorsurface of the solid plate. The housing stop portion may be directlyadjacent to the exterior surface of the solid plate (a surface of theplate facing away from the stack). However, in some embodiments, thehousing stop portion is indirectly adjacent to the exterior surface ofthe solid plate such that one or more intervening components (e.g.,washers, layers of material, etc.) is between the housing stop portionand the exterior surface of the solid plate. The housing stop portionmay be discrete from the solid housing component and/or the solid plate.The housing stop portion may be made of any of a variety of materials,such as a metal (e.g., aluminum or titanium), a metal alloy (e.g.,stainless steel), a composite (e.g., carbon fiber), a polymeric material(e.g., a rigid plastic), or a combination thereof. The housing stopportion may have any of a variety of shapes depending on, for example, adesired deflection of the solid plate and/or pressure distributionwithin the battery. It has been realized that some shapes of housingstop portions (e.g., elongated bars, or rings (e.g., rectangular ornon-rectangular rings) conforming to a perimeter of the solid plate) candistribute force (e.g., from tension in the solid housing component)across the face of the solid plate more uniformly than, for example,solid plates coupled via discrete auxiliary fasteners (e.g., bolts withnuts) in contact with relatively small areas of the solid plate.

Referring to FIGS. 7A-7C, exemplary battery 100 may be configured suchthat first solid housing component 314 is coupled to first solid plate310 via coupling of the first solid housing component 314 to firsthousing stop portion 360 adjacent to exterior surface 335 of first solidplate 310. Optionally, in some embodiments first solid housing component314 is coupled to optional second solid plate 312 via coupling of firstsolid housing component 314 to optional second housing stop portion 362adjacent to exterior surface 337 of optional second solid plate 312.Optionally, exemplary battery 100 may further be configured asillustrated in FIGS. 7A-7C, such that optional second solid housingcomponent 316 is coupled to first solid plate 310 via coupling ofoptional second solid housing component 316 to third housing stopportion 364 adjacent to exterior surface 335 of first solid plate 310,as well as to optional second solid plate 312 via coupling of firstsolid housing component 314 to optional fourth housing stop portion 366adjacent to exterior surface 337 of optional second plate 312. Thecouplings between exemplary housing stop portions and exemplary solidhousing components may comprise, for example, welds, fasteners,adhesives, or combinations thereof. A housing of this type may, in someembodiments, decrease a largest lateral pressure-applying dimension ofthe housing relative to a housing comprising, for example, fastenerscoupling solid plates.

FIG. 7A shows a front view schematic illustration of exemplary battery100 in one embodiment, where all housing stop portions are identical.FIG. 7B shows an exploded perspective of the same exemplary battery 100,and FIG. 7C shows a perspective illustration of the same exemplarybattery 100. It should be understood that other embodiments, wherehousing stop portions have different geometries from each other, arepossible, as are embodiments with more or fewer solid housing componentsand/or housing stop portions. In some embodiments, stop portions arediscrete, as illustrated by FIGS. 7A-7C. However, in some embodiments,stop portions are portions of a single unitary object connected tomultiple solid housing components (e.g., a first solid housing componentand a second solid housing component). For example, FIGS. 7D-7Eillustrate an embodiment where stop portion 360 and stop portion 364 areportions of single unitary object 321. The geometry of the stop portionmay be configured to apply force to and/or support a relatively largearea of the solid plate, in contrast to auxiliary fasteners (e.g., abolt and nut), which may apply pressure in a fairly localized region. Insome embodiments, at least 50%, at least 60%, at least 75%, at least90%, at least 95%, at least 99%, or 100% of a perimeter of an exteriorsurface of a solid plate is covered by (e.g., adjacent to) one or morehousing stop portions.

The solid housing component may be coupled to the housing stop portionvia any of a variety of suitable techniques. For example, the solidhousing component may be coupled to the housing stop portion via a weld,a fastener, an adhesive, or a combination thereof.

In some embodiments, the solid housing component is coupled to the solidplate via a lateral portion of the solid housing component adjacent toan exterior surface of the solid plate. A lateral portion of the solidhousing component refers to one which can be substantially parallel to alateral surface of the solid plate when the solid housing component andthe solid plate are coupled in the housing of the battery. For example,referring to FIGS. 8A-8C, exemplary battery 100 may be configured suchthat first solid housing component 314 is coupled to first solid plate310 via first lateral portion 370 of first solid housing component 314adjacent to exterior surface 335 of first solid plate 310. In FIG. 8A,first lateral portion 370 is substantially parallel to exterior surface335 of solid plate 310, in accordance with some embodiments. Optionally,in some embodiments first solid housing component 314 is coupled tooptional second solid plate 312 via second lateral portion 372 ofoptional second solid housing component 316 adjacent to exterior surface337 of optional second solid plate 312. In some embodiments, theexemplary battery may further be configured as illustrated in FIGS.8A-8C, such that optional second solid housing component 316 is coupledto first solid plate 310 via third lateral portion 374 of optionalsecond solid housing component 316 adjacent to exterior surface 335 offirst solid plate 310, and such that optional second solid housingcomponent 316 is coupled to optional second solid plate 312 via fourthlateral portion 376 of optional second solid housing component 316adjacent to exterior surface 337 of optional second solid plate 312.When the solid housing component coupled to the solid plate is intension, the lateral portion of the solid plate may apply a force to atleast a portion of the solid plate. For example, in FIGS. 8A-8C, tensionin first solid housing component 304 may cause lateral portion 370 topress against exterior surface 335 of solid plate 310, thereby causingstack 304 to experience an anisotropic compressive force having acomponent in the direction of arrow 182 in FIG. 8A).

The lateral portion of the solid housing component may have any of avariety of shapes depending on, for example, a desired deflection of thesolid plate and/or pressure distribution within the battery. It has beenrealized that some shapes of lateral portions (e.g., relatively flatportions) can distribute force (e.g., from tension in the solid housingcomponent) across the face of the solid plate more uniformly than, forexample, solid plates coupled via discrete auxiliary fasteners (e.g.,bolts with nuts) in contact with relatively small areas of the solidplate. A housing of this type may, in some embodiments, decrease alargest lateral pressure-applying dimension of the housing relative to ahousing comprising, for example, auxiliary fasteners coupling solidplates.

FIG. 8A shows a front view schematic illustration of exemplary battery100 in one embodiment, where all the lateral portions are identical.FIG. 8B shows an exploded schematic illustration of the same exemplarybattery 100, and FIG. 8C shows a perspective schematic illustration ofthe same exemplary battery 100. It should be understood that otherembodiments, where lateral portions have different geometries from eachother, are possible, as are embodiments with more or fewer solid housingcomponents and/or lateral portions of solid housing components.

The lateral portion of the solid housing component may be directlyadjacent to the exterior surface of the solid plate (a surface of theplate facing away from the stack). However, in some embodiments, thelateral portion is indirectly adjacent to the exterior surface of thesolid plate such that one or more intervening components (e.g., washers,layers of material, etc.) is between the lateral portion of the solidhousing component and the exterior surface of the solid plate. In someembodiments, the lateral portion of the solid housing component and aremainder of the solid housing component form a unitary object.

In some embodiments, the solid housing component contributes to forceapplication by covering at least a portion (e.g., at least 10%, at least25%, at least 50%, at least 75%, at least 90%, at least 95%, or all) ofa first end of the stack comprising the first electrochemical cell andthe second electrochemical cell. While in some embodiments a solidhousing component directly covers at least a portion of an end of thestack (e.g., is directly adjacent), in some embodiments, the solidhousing component covers at least a portion of an intervening component(e.g., a first solid plate) or part of a housing frame covering at leasta portion of the end of the stack. In some embodiments, a second solidhousing component contributes to force application by covering at leasta portion of a second end of the stack. For example, referring to thecross-sectional schematic diagram in FIG. 9 , housing 302 comprisesfirst solid housing component 314 (which covers second end 308 of stack304, and which has a portion along at least some of side 380 of thestack). Tension in first solid housing component 314 and in second solidhousing component 316 may contribute force compressing stack 304,thereby applying an anisotropic force in direction of arrow 181 havingcomponent 182 normal to a first electrode active surface of firstelectrochemical cell 110 and/or a second electrode active surface ofsecond electrochemical cell 120.

In some embodiments, the first solid housing component covers a portion(e.g., at least 10%, at least 25%, at least 50%, at least 75%, at least90%, at least 95%, or all) of the first end of the stack and has aportion along at least some of the side of the stack. In someembodiments, a second solid housing component covers at least a portion(e.g., at least 10%, at least 25%, at least 50%, at least 75%, at least90%, at least 95%, or all) of the second end of the stack a portionalong at least some of the side of the stack. The first solid housingcomponent and second solid housing component may be coupled directly orindirectly. Such a coupling be accomplished in any of a variety ofsuitable ways. For example, in some embodiments, a point of attachmentbetween the first solid housing component and the second solid housingcomponent is at a region of overlap between the first solid housingcomponent and the second solid housing component along the side of thestack. It should be understood that a point of attachment may be part ofa region of attachment between two surfaces (e.g., a region along a lineof attached points, or a region occupying a 2-dimensional set ofattached points), and is not meant to apply that an entirety ofattachment is limited to a single point. It has been realized that, insome such embodiments, certain coupling techniques may establishcoupling while maintaining relatively small lateral profiles for thehousing, while maintaining an ability for the housing to apply and/ormaintain an anisotropic force with a component normal to an activesurface of one or more electrochemical cells of the stack. In someembodiments, the point of attachment between the first solid housingcomponent and the second solid housing component comprises a weld, afastener, an adhesive, friction, a joint, or a combination thereof.Referring to FIG. 9 , which shows a cross-sectional schematicillustration of exemplary battery 100, first solid housing component 314and second solid housing component 316 are coupled at point ofattachment 382 at region of overlap 384 along side 380 of stack 304, inaccordance with some embodiments. A similar point of attachment may bepresent at a region of overlap at an opposite side of the stack. Ahousing of this type may, in some embodiments, decrease a largestlateral pressure-applying dimension of the housing relative to a housingcomprising, for example, auxiliary fasteners coupling solid plates. Insome embodiments, the stack comprises one or more solid plates. Forexample, though not shown in FIG. 9 , a solid plate of the same type assolid plate 310 in FIG. 4 may be between first solid housing component314 and first electrochemical cell 110. The solid plate may be a firstsolid plate, and the stack may further comprise a second solid platebetween the second solid housing component and the secondelectrochemical cell.

In some embodiments, the housing comprises a first solid plate coveringat least a portion (e.g., at least 10%, at least 25%, at least 50%, atleast 75%, at least 90%, at least 95%, or all) of the first end of thestack and a second solid plate covering at least a portion (e.g., atleast 10%, at least 25%, at least 50%, at least 75%, at least 90%, atleast 95%, or all) of the second end of the stack. In some suchembodiments, a solid housing component possesses features thatmechanically interlock with features along a lateral edge of the firstsolid plate to establish a joint. In some embodiments, the first solidhousing component possesses features that mechanically interlock withfeatures along a lateral edge of the second solid plate, establishing asecond joint. In some embodiments, a second solid housing componentpossesses features that mechanically interlock with features along alateral edge of the first plate and features along a lateral edge of thesecond plate to form a third joint and a fourth joint, respectively.Mechanically interlocking features may be designed to interlock in anyof a variety of suitable ways, including, but not limited to,interdigitation of features, formation of woodworking joints (e.g.dovetail joints, Knapp joints, lap joints, box joints), or by amechanical clipping mechanism. It has been realized that certainmechanically interlocking features may establish coupling whilemaintaining relatively small lateral profiles for the housing. Forexample, referring to the schematic cross-sectional illustration in FIG.10 , housing 302 of battery 100 comprises first solid plate 310 coveringat least a portion of first end 306 of stack 304, as well as secondsolid plate 312 covering second end 308 of stack 304. First solidhousing component 314 possesses features 390 that mechanically interlockwith features 392 along lateral edges of first solid plate 310 toestablish first joint 394 between first solid housing component 314 andfirst solid plate 310. Similar interlocking features establish secondjoint 396 between first solid housing component 314 and second solidplate 312, as well as third joint 398 between second solid housingcomponent 314 and first solid plate 310 and fourth joint 400 betweensecond solid housing component 314 and second solid plate 312. A housingof this type may, in some embodiments, decrease a largest lateralpressure-applying dimension of the housing relative to a housingcomprising, for example, auxiliary fasteners coupling solid plates. Insome embodiments, an adhesive further coupled the solid housingcomponent and the solid plate (e.g., at interfaces between themechanically interlocking features).

In some embodiments, the first solid housing component covers at least aportion (e.g., at least 10%, at least 25%, at least 50%, at least 75%,at least 90%, at least 95%, or all) of the first end of the stack andhas a portion along at least some of the side of the stack. In someembodiments, a second solid housing component covers at least portion(e.g., at least 10%, at least 25%, at least 50%, at least 75%, at least90%, at least 95%, or all) of the second end of the stack and has aportion along at least some of the side of the stack. In someembodiments, first solid housing component and the second solid housingcomponent are each mechanically joined with at least one additionalsolid housing component (e.g., along a side of the stack). The at leastone additional solid housing component may be coupled to the first solidhousing component at a first region of overlap, and coupled to thesecond solid housing component at a second region of overlap. It hasbeen realized that, in some embodiments, certain coupling techniques mayestablish coupling while maintaining relatively small lateral profilesfor the housing. In some embodiments, the couplings between the solidhousing components comprise welds, joints, and/or adhesives.

Referring to the cross-sectional schematic diagram in FIG. 11 , firstsolid housing component 314 and second solid housing component 316 ofhousing 302 are coupled to additional solid housing component 404 ofhousing 302. First solid housing component 314 forms first region ofoverlap 406 with additional solid housing component 404, where the twohousing components are mechanically joined (e.g., via a weld, anadhesive, friction, a fastener, etc.), in accordance with someembodiments. Second solid housing component 316 forms second region ofoverlap 408 with additional solid housing component 404, where the twohousing components are mechanically joined (e.g., via a weld, anadhesive, friction, a fastener, etc.), in accordance with someembodiments. In some embodiments, such as the embodiment illustrated inFIG. 11 , second additional housing component 410 may form third regionof overlap 412 with first solid housing component 314 where the twosolid housing components are mechanically joined, and may form fourthregion of overlap 414 with second solid housing component 316 where thetwo solid housing components are mechanically joined, howeverembodiments with more or fewer additional housing components are alsocontemplated. A housing of this type may, in some embodiments, decreasea largest lateral pressure-applying dimension of the housing relative toa housing comprising, for example, auxiliary fasteners coupling solidplates.

Some embodiments comprise applying an external anisotropic force to astack at least partially enclosed by a housing described above (e.g.,with one or more solid housing components), the stack comprising a firstelectrochemical cell and a second electrochemical cell. As mentionedabove, the external anisotropic force may have a component normal to afirst electrode active surface of the first electrochemical cell and/ora second electrode active surface of the second electrochemical cell.The external anisotropic force may be applied via a pressure applicationdevice/system external to the battery (e.g., an external clamp, ahydraulic press, etc.), and may be applied, for example, duringmanufacture of a battery comprising the stack and the housing. Theexternal anisotropic force may define a pressure of at least 10 kgf/cm²,at least 12 kgf/cm², at least 20 kgf/cm², at least 25 kgf/cm² and/or upto 30 kgf/cm², up to 35 kgf/cm², up to 40 kgf/cm², or more. Someembodiments of such housings are described above.

In some embodiments, pressure on the stack is maintained via one or morecomponents of the housing. For example, in some embodiments, a firstsolid housing component of the housing is attached during to a second,solid housing component during at least a portion of the step ofapplying the external anisotropic force. In some embodiments, a solidhousing component is attached to a first solid plate covering at least aportion of a first end of the stack during at least a portion of thestep of applying the external anisotropic force. In some suchembodiments, the solid housing component is attached to a second solidplate covering at least a portion of a second end of the stack during atleast a portion of the step of applying the external anisotropic force.In some embodiments, a first solid housing component is attached to asecond discrete solid housing component during at least a portion of thestep of applying the external anisotropic force by attaching the firstsolid housing component to one or more additional solid housingcomponents that are attached to the second solid housing component.

In some embodiments, attaching the first solid housing component to thesecond solid housing component or to one or more additional solidhousing comprises welding (e.g., laser welding) the first housingcomponent and the second housing component together. In someembodiments, attaching the first solid housing component to the secondsolid housing component or to one or more additional solid housingcomprises applying a fastener (e.g., a screw, a rivet, etc.) to thefirst housing component and the second housing component. In someembodiments, attaching the first solid housing component to the secondsolid housing component or to one or more additional solid housingcomprises applying an adhesive to the first housing component and thesecond housing component, thereby forming an adhesive interaction. Insome embodiments, attaching a solid housing component to the first solidplate and/or the second solid plate comprises establishing a joint bymechanically interlocking features of the solid housing component and alateral edge of the first solid plate and/or second solid plate.

Subsequently, some embodiments include removing the applied externalanisotropic force while maintaining, via tension in the attached firstsolid housing component and the second solid housing component, ananisotropic force having a component normal to the first electrodeactive surface and/or the second electrode active surface. Theanisotropic force may have a component normal to the first electrodeactive surface of the first electrochemical cell of the stack and/or thesecond electrode active surface of the second electrochemical cell ofthe stack. As above, the anisotropic force may define a pressure of atleast 10 kgf/cm², at least 12 kgf/cm², at least 20 kgf/cm², at least 25kgf/cm² and/or up to 30 kgf/cm², up to 35 kgf/cm², up to 40 kgf/cm², ormore. It has been realized that by applying an initial force the stackand subsequently establishing tension in one or more parts of thehousing (e.g., a solid housing component and/or a solid plate),relatively high pressures may be established in the stack at a point ofmanufacture within a substantially fixed housing. Some suchconfigurations may reduce a number of parts required for the overallbattery, e.g., by avoiding use of tension in auxiliary fasteners (e.g.,with separate screws or threaded rods, nuts, washers, etc.). A reductionin number of parts and/or fasteners in the housing may promote anoverall reduction in housing and/or battery volume, which may bedesirable in some applications.

In some embodiments, the solid housing component (e.g., a first solidhousing component, a second solid housing component) comprises a solidsheet. It should be understood that in this context a solid sheet refersgenerally to an overall shape and aspect ratio of an object. A solidsheet need not be completely flat or completely planar to be considereda solid sheet. For example, a solid sheet can have surfaces forming anangle, such as solid housing object 314 in FIG. 9 . In some embodiments,the solid housing component has a relatively large aspect ratio in termsof its lateral dimensions versus its thickness dimension. In someembodiments, a ratio of at least one (or all) lateral dimensions of thesolid housing component to the thickness of the solid housing componentis greater than or equal to 1.5, greater than or equal to 2, greaterthan or equal to 5, greater than or equal to 10, greater than or equalto 20, greater than or equal to 50, greater than or equal to 100,greater than or equal to 500, and/or up to 1000, up to 5000, or greater.In some embodiments, the solid housing component (e.g., comprising asolid sheet) has a relatively small thickness. Having a relatively smallthickness (e.g., compared thickness of other components of the batterysuch as the electrochemical cells, solid plates when present, etc.) maycontribute to the housing having a relatively small lateral profile,which may promote overall small volumes for the battery. In someembodiments, the solid housing component (e.g., comprising a solidsheet) has a thickness of less than or equal to 5 mm, less than or equalto 2 mm, less than or equal to 1 mm, less than or equal to 500 microns,and/or as low as 200 microns or less. In some embodiments, the solidhousing component (e.g., first solid housing component, second solidhousing component) comprises a metal and/or metal alloy sheet, such asan aluminum (e.g., aluminum metal) sheet.

In some embodiments, the battery further comprises a contoured solidarticle portion between a lateral exterior surface of the firstelectrochemical cell and a portion of the housing. The contoured solidarticle portion may comprise a surface adjacent (e.g., directly adjacentor indirectly adjacent) to the lateral exterior surface of the firstelectrochemical cell that is convex with respect to the lateral exteriorsurface in the absence of an applied force. In some embodiments, underat least one magnitude of applied force, the surface of the contouredsolid article portion becomes less convex. Referring to thecross-sectional schematic diagram of battery in FIG. 12 , battery 100may comprise contoured solid article portion 402 between lateralexterior surface 403 of electrochemical cell 110 and a portion ofhousing 102, in accordance with certain embodiments. Surface 404 ofcontoured solid article portion 402, which is adjacent to lateralexterior surface 403, is convex with respect to lateral exterior surface403 in the absence of an applied force. In some embodiments, thecontoured solid article portion is a discrete article with respect tothe housing. The contoured solid article portion may be between thelateral exterior surface of the first electrochemical cell and, forexample, a solid plate of the housing and/or a solid housing componentdescribed above.

In some embodiments, under at least one magnitude of applied force, thesurface of the contoured solid article portion becomes less convex. Sucha change in convexity may be caused by force-induced deformation of thecontoured solid article portion. For example, during application of atleast one magnitude of an anisotropic force having a component normal toan active surface of an electrode of the first electrochemical cell, thesurface of the contoured solid article portion may become less convex.

As would be understood by one of ordinary skill in the art, a solidsurface that has a given shape “in the absence of an applied force” isone that, when all external forces are removed from the objectcomprising that surface, always assumes that particular shape.Accordingly, a surface that has a convex shape in the absence of anapplied force is one that always assumes a convex shape when allexternal forces are removed from the object comprising that surface.Generally, a first surface is convex with respect to a second surfacewhen the first surface curves away from the second surface. It should beunderstood that portions of surfaces being convex with respect to othersurfaces refers to the external geometric surface of the portion. Anexternal geometric surface of an object refers to the surface definingthe outer boundaries of the object when analyzed on substantially thesame scale as the maximum cross-sectional dimension of the object.Generally, the external geometric surface of an object does not includethe internal surfaces, such as the surface defined by pores within aporous object.

It has been observed in the context of this disclosure that the presenceof a contoured solid article portion can promote a desired pressuredistribution experienced by one or more (or all) of the active surfacesof the electrochemical cells of the battery. For example, in some cases,a uniform pressure distribution is achieved. Such desired pressuredistributions can, in some cases, lead to improved performance of thebattery. The deformation of the contoured solid article portion (e.g.,to become less convex) under applied force may, in some instances,reduce potentially deleterious effects in pressure distribution causedby deformation (e.g., deflection) of portions of the housing (e.g.,solid plates) during application of pressure. Further description ofcontoured surfaces and related devices and methods is provided inInternational Application No. PCT/US2020/038375, filed on Jun. 18, 2020,and entitled “Methods, Systems, and Devices for Applying Forces toElectrochemical Devices,” which is incorporated herein by reference inits entirety.

In some embodiments, the contoured solid article portion (e.g., that ispart of a device configured to apply a force to an electrochemicaldevice) comprises any suitable solid material. In some embodiments, thecontoured solid article portion is or comprises a metal, metal alloy,composite material, or a combination thereof. In some cases, the metalthat the contoured solid article portion is or comprises is a transitionmetal. For example, in some embodiments, the contoured solid articleportion is or comprises Ti, Cr, Mn, Fe, Co, Ni, Cu, or a combinationthereof. In some embodiments, the contoured solid article portion is orcomprises a non-transition metal. For example, in some embodiments, thecontoured solid article portion is or comprises Al, Zn, or combinationsthereof. Exemplary metal alloys that the contoured solid article portioncan be or comprise include alloys of aluminum, alloys of iron (e.g.,stainless steel), or combinations thereof. Exemplary composite materialsthat the contoured solid article portion can be or comprise include, butare not limited to, reinforced polymeric, metallic, or ceramic materials(e.g., fiber-reinforced composite materials), carbon-containingcomposites, or combinations thereof.

In some embodiments, the contoured solid article portion comprising thesolid surface (e.g., convex surface) comprises a polymeric material(e.g., an organic polymeric material). In some such embodiments, thecontoured solid article portion comprises a polymeric material (e.g., anorganic polymeric material) in an amount of greater than or equal to 25weight percent (wt %), greater than or equal to 50 wt %, greater than orequal to 75 wt %, greater than or equal to 90 wt %, greater than orequal to 95 wt %, greater than or equal to 99 wt %, or up to 100 wt %.Example of suitable polymeric materials include, but are not limited to,acrylonitrile butadiene styrene, polylactic acid, polyamide, polyetherether ketone, Nylon, polycarbonate, polyetherimide resin, orcombinations thereof. A contoured solid article portion comprising apolymeric material may be relatively inexpensive to fabricate and maydeform relatively easily compared to other types of materials.

The contoured solid article portion may have any of a variety ofsuitable elastic moduli. The elastic modulus of the contoured solidarticle portion may be high enough such that it can adequately hold itsshape. In some embodiments, the contoured solid article portion has anelastic modulus of greater than or equal to 10 MPa, greater than orequal to 50 MPa, greater than or equal to 100 MPa, greater than or equalto 200 MPa, greater than or equal to 500 MPa, greater than or equal to 1GPa, greater than or equal to 2 GPa, greater than or equal to 5 GPa,greater than or equal to 10 GPa, greater than or equal to 20 GPa,greater than or equal to 50 GPa, greater than or equal to 100 GPa,greater than or equal to 200 GPa, or greater. In some embodiments, thecontoured solid article portion comprising the solid surface has anelastic modulus of less than or equal to 800 GPa, less than or equal to760 GPa, less than or equal to 500 GPa, less than or equal to 400 GPa,less than or equal to 300 GPa, less than or equal to 250 GPa, less thanor equal to 200 GPa, less than or equal to 150 GPa, less than or equalto 100 GPa, less than or equal to 75 GPa, less than or equal to 50 GPa,less than or equal to 25 GPa, less than or equal to 10 GPa, less than orequal to 5 GPa, or lower). Combinations of these ranges are possible(e.g., greater than or equal to 10 MPa and less than or equal to 800GPa, greater than or equal to 1 GPa and less than or equal to 250 GPa).Materials having a low elastic modulus tend to deform under a given loadmore than materials having a high elastic modulus.

As mentioned above, the battery may comprise components having apotentially advantageous arrangement (e.g., for thermal management). Forexample, in some embodiments, a multicomponent stack is describedcomprising electrochemical cells, thermally conductive solid articleportions, and thermally insulating compressible solid article portions.The multicomponent stack or stack of electrochemical cells may be partof a battery described herein. In some embodiments, a multicomponentstack comprises the following in the order listed: a firstelectrochemical cell; a first thermally conductive solid articleportion; a thermally insulating compressible solid article portion; asecond thermally conductive solid article portion; and a secondelectrochemical cell. For example, referring to FIG. 13A, battery 100comprises a multicomponent stack comprising first electrochemical cell110, first thermally conductive solid article portion 131, thermallyinsulating compressible solid article portion 140, second thermallyconductive solid article portion 132, and second electrochemical cell120. This arrangement of thermally conductive and thermally insulatingcomponents may facilitate relatively rapid transfer of heat away fromelectrochemical cells in the stack while mitigating thermal transferbetween electrochemical cells of the stack. For example, battery 100 mayhave a relatively low rate of thermal transfer in thickness direction153 shown in FIG. 13A, while at least a portion of battery 100 may havea relatively high rate of thermal transfer in lateral direction 151 asshown in FIG. 13A. Additionally, having one or more of the components becompressible may assist with mitigating expansion of the battery, e.g.,during cumulative expansion of electrochemical cells during cycling. Thestack may be at least partially enclosed by a housing. For example,battery 100 may be at least partially enclosed by optional housing 102in FIG. 13B. In some, but not necessarily all embodiments, there are nointervening layers or components between these articles. For example, insome embodiments, the first electrochemical cell is directly adjacent tothe first thermally conductive solid article portion, the firstthermally conductive solid article portion is directly adjacent to thethermally insulating compressible solid article portion, the thermallyinsulating compressible solid article portion is directly adjacent tothe second thermally conductive solid article portion, and the secondthermally conductive solid article portion is directly adjacent to thesecond electrochemical cell. However, in other embodiments, interveningarticles or layers may be present, such as sensors (e.g., pressuresensors, temperature sensors, etc.). In some embodiments, at least onelateral edge of the thermally conductive solid article portion extendspast a lateral edge of the first electrochemical cell. For example, inFIG. 13A lateral edge 156 of first thermally conductive solid articleportion 131 extends past lateral edge 158 of first electrochemical cell110, in accordance with certain embodiments. This may facilitate removalof heat from the electrochemical cells.

As mentioned above, some embodiments may comprise application of ananisotropic force (e.g., via a solid plate). FIGS. 14A-14B show one suchembodiment, where anisotropic force 181 is applied via first solid plate201 (see FIG. 14B). FIG. 14B illustrates how in some embodiments, theapplication of such a force causes thermally insulating compressiblesolid article portion 140 to compress.

In some embodiments, the battery comprises thermally conductive solidarticle portions. For example, referring back to FIGS. 13A-13B, battery100 comprises first thermally conductive solid article portion 131 andsecond thermally conductive solid article portion 132. As mentionedabove, the thermally conductive solid article portions may promote heattransfer away from components of the battery (e.g., the electrochemicalcells) while also facilitating alignment of electrochemical activeregions of the electrochemical cells. In some, but not necessarily all,cases thermally conductive solid article portions are in direct contactwith the electrochemical cells. For example, in FIGS. 13A-13B, firstthermally conductive solid article portion 131 is shown as being indirect contact with first electrochemical cell 110. However, directcontact is not required, and in some embodiments, there are one or moreintervening components (e.g., sensors, etc.) between the thermallyconductive solid article portions and the electrochemical cells.

In some embodiments, the thermally conductive solid article portion ofthe battery has a relatively high effective thermal conductivity. Asmentioned above, such a high effective thermal conductivity may allowthe thermally conductive solid article to assist with dissipating heatfrom one or more electrochemical cells of the battery. Thermalconductivity is generally understood to be an intrinsic property of amaterial related to its ability to conduct heat. Thermal conductivity isa temperature-dependent quantity and is typically reported in units of Wm⁻¹ K⁻¹. The effective thermal conductivity of an article generallyrefers to the ability of an article to conduct heat, taking into accountthat the article may be made of a single material or may anon-homogeneous material that may be made of a combination of materials(e.g., a composite material such as a particulate material or layeredmaterial). An exemplary method for measuring the thermal conductivity oreffective thermal conductivity of a thermally insulating compressiblesolid article portion is using a hot disk method, as described inISO/DIS 22007-2.2.

In some embodiments, a thermally conductive solid article portion (e.g.,first thermally conductive solid article portion, second thermallyconductive solid article portion) has a relatively high effectivethermal conductivity in an in-plane direction. Referring again to FIG.13A, for example, first thermally conductive solid article portion 131and/or second thermally conductive solid article portion 132 may have ahigh effective thermal conductivity in lateral direction 151, which isparallel to the in-plane directions of first thermally conductive solidarticle portion 131 and/or second thermally conductive solid articleportion 132. As a result, first thermally conductive solid articleportion 131 and/or second thermally conductive solid article portion 132may enhance the rate at which heat conducted from first electrochemicalcell 110 and/or second electrochemical cell 120 is then transferred away(in a lateral direction) from first electrochemical cell 110 and/orsecond electrochemical cell 120, according to certain embodiments. Aresulting accelerated rate of cooling of the electrochemical cells mayoccur, and in combination with a reduced extent of heat transfer in thethickness direction can, in some instances, improve the safety andperformance of the battery (e.g., by reducing thermal propagation). Insome embodiments, a thermally conductive solid article portion (e.g.,first thermally conductive solid article portion, second thermallyconductive solid article portion) has an effective thermal conductivityof greater than or equal to 10 W m⁻¹ K⁻¹, greater than or equal to 25 Wm⁻¹ K⁻¹, greater than or equal to 50 W m⁻¹ K⁻¹, greater than or equal to65 W m⁻¹ K⁻¹, greater than or equal to 80 W m⁻¹ K⁻¹, greater than orequal to 100 W m⁻¹ K⁻¹, greater than or equal to 150 W m⁻¹ K⁻¹, and/orup to 159 W m⁻¹ K⁻¹, up to 200 W m⁻¹ K⁻¹, or greater in an in-planedirection at a temperature of 25° C. For example a thermally conductivesolid article portion (e.g., first thermally conductive solid articleportion, second thermally conductive solid article portion) may be madeof aluminum and have an effective thermal conductivity of 159 W m⁻¹ K⁻¹in an in-plane direction at a temperature of 25° C. The thermallyconductive solid article portion (e.g., first thermally conductive solidarticle portion, second thermally conductive solid article portion) maycomprise any of a variety of suitable materials. In some embodiments, athermally conductive solid article portion (e.g., first thermallyconductive solid article portion, second thermally conductive solidarticle portion) comprises a metal and/or metal alloy. Exemplary metalsinclude, but are not limited to transition metals (e.g., titanium,manganese, iron, nickel, copper, zinc), non-transition metals (e.g.,aluminum), and alloys or other combinations thereof. In certainembodiments, a thermally conductive solid article portion (e.g., firstthermally conductive solid article portion, second thermally conductivesolid article portion) comprises or is made of aluminum, at leastbecause aluminum has a relatively high effective thermal conductivityand a relatively low mass density, which in some cases contributes to anoverall high specific energy density for the battery. One exemplary typeof aluminum material of which a thermally conductive solid articleportion may be made is 3003 H14 series aluminum, which is aluminumalloyed with 1.2% manganese to increase strength. In some embodiments, arelatively high percentage (e.g., greater than or equal to 50 weightpercent (wt %), greater than or equal to 75 wt %, greater than or equalto 90 wt %, greater than or equal to 95 wt %, greater than or equal to99 wt %, or more) of the thermally conductive solid article portion ismetal and/or metal alloy.

In some embodiments, the thermally conductive solid article portioncomprises or is made of a carbon-based material. Suitable carbon-basedmaterials include, but are not limited to, graphite, carbon-fiber,graphene (e.g., as part of thermally conductive solid article comprisinga solid substrate and associated with graphene), and combinationsthereof. In some embodiments, the carbon-based material is present in arelatively high percentage (e.g., greater than or equal to 50 wt %,greater than or equal to 75 wt %, greater than or equal to 90 wt %,greater than or equal to 95 wt %, greater than or equal to 99 wt %, ormore) of the thermally conductive solid article portion. In someembodiments, a carbon-based material of a thermally conductive solidarticle portion has graphite, carbon-fiber, graphene, or a combinationthereof present in an amount of at least 25 wt %, at least 50 wt %, atleast 75 wt %, at least 90 wt %, at least 95 wt %, at least 99 wt %, or100 wt %.

The thermally conductive solid article portion (e.g., first thermallyconductive solid article portion, second thermally conductive solidarticle portion) may have any of a variety of form factors. In someembodiments, the thermally conductive solid article portion (e.g., firstthermally conductive solid article portion, second thermally conductivesolid article portion) is in the form of a relatively planar object(notwithstanding the non-planarities and/or alignment features describedbelow). For example, the thermally conductive solid article portion(e.g., first thermally conductive solid article portion, secondthermally conductive solid article portion) may be in the form of asheet (e.g., a metal and/or metal alloy sheet). In some embodiments, thethermally conductive solid article portion (e.g., first thermallyconductive solid article portion, second thermally conductive solidarticle portion) is or comprises a fin (e.g., a metal and/or metal alloyfin). In some embodiments, the thermally conductive solid articleportion (e.g., first thermally conductive solid article portion, secondthermally conductive solid article portion) is or comprises a solidplate. It should be understood that the surfaces of a sheet, fin, orsolid plate do not necessarily need to be flat. For example, one of thesides of a sheet, fin, or solid plate could have any of thenon-planarities and/or alignment features described herein.

The thermally conductive solid article portion (e.g., first thermallyconductive solid article portion, second thermally conductive solidarticle portion) may have a thickness as well as two orthogonal lateraldimensions that are orthogonal to each other as well as orthogonal tothe thickness. For example, referring to FIG. 13A, first thermallyconductive solid article portion 131 has maximum thickness 235, lateraldimension 151, and a second lateral dimension (not pictured) orthogonalto both maximum thickness 235 and lateral dimension 151 (which would runinto and out of the plane of the drawing in FIG. 13A).

The dimensions of the thermally conductive solid article portion may bechosen based on any of a variety of considerations. For example, thethickness or lateral dimensions may be chosen based on the desired totalsize of the battery and/or a desired pack burden. In some embodiments,one or more lateral dimensions of the thermally conductive solid articleportion is such that heat generated by the electrochemical cells, onceconducted to the thermally conductive solid article portions, can betransferred a relatively long distance from the electrochemical activeregions of the electrochemical cells. In some embodiments, the thermallyconductive solid article portion has one or more lateral dimensions thatextends at least 1 mm, at least 2 mm, at least 5 mm, at least 1 cm, atleast 2 cm, at least 5 cm, and/or up to 10 cm or more past theelectrochemical active region of the electrochemical cell coupled to thethermally conductive solid article portion.

In some embodiments, the thermally conductive solid article portion(e.g., first thermally conductive solid article portion, secondthermally conductive solid article portion) has at least one lateraldimension that is at least 5 times, at least 10 times, and/or up to 20times, up to 50 times, up to 100 times or more greater than the maximumthickness of the thermally conductive solid article portion.

In some embodiments, the battery comprises a thermally insulatingcompressible solid article portion. The thermally insulatingcompressible solid article portion may be between two electrochemicalcells of the battery. For example, referring back to FIGS. 13A-13B,battery 100 comprises thermally insulating compressible solid articleportion 140 between first electrochemical cell 110 and secondelectrochemical cell 120, according to certain embodiments. A moredetailed description of exemplary thermally insulating compressiblesolid article portions is described below.

In some embodiments, the thermally conductive solid article portion isrelatively smooth as compared to the thermally insulating compressiblesolid article portion. This may, in some cases, be advantageous,because, under high magnitudes of force, surface irregularities incertain types of thermally insulating compressible solid articleportions (e.g., microcellular foams) may cause non-uniform pressuredistributions on the electrode active surfaces of the battery. Arelatively smooth thermally conductive solid article portion (e.g., ametal sheet) may, comparatively, have few irregularities and “smooth”out the pressure distribution. As one example, in FIG. 15 , surface 144of thermally insulating compressible solid article portion 140 may berelatively rough (e.g., have a relatively high surface roughness), whilesurface 334 of first thermally conductive solid article portion 131 maybe relatively smooth (e.g., have a relatively low surface roughness),thereby mitigating irregularities in pressure distribution to surface116 of first electrochemical cell 110. In some embodiments, thethermally conductive solid article portion has a surface facing asurface of the first electrochemical device having a surface roughnessof less than or equal to 10 micrometers, less than or equal to 5micrometers, less than or equal to 1 micrometer, less than or equal to0.5 micrometers, less than or equal to 0.1 micrometers, less than orequal to 0.05 micrometers, less than or equal to 0.01 micrometers, orless. In some embodiments, the thermally conductive solid articleportion has a surface facing a surface of the first electrochemicaldevice having a surface roughness as low as 0.005 micrometers. That isto say, in some embodiments, the thermally conductive solid articleportion has a surface having a surface roughness as low as 0.005micrometers, with that surface facing a surface of the firstelectrochemical device.

In some embodiments, the arrangement of components of the battery may berepeated. For example, in FIG. 16 , battery 400 comprises firstelectrochemical cell 110, first thermally conductive solid articleportion 131, first thermally insulating compressible solid articleportion 140, second thermally conductive solid article portion 132,second electrochemical cell 120, third thermally conductive solidarticle portion 231, second thermally insulating compressible solidarticle portion 240, fourth thermally conductive solid article portion232, and third electrochemical cell 210.

In certain aspects, batteries with components that may facilitatealignment of electrochemical active areas are generally described. FIG.17 is a schematic diagram of a non-limiting embodiment of battery 100.Battery 100 in FIG. 1 comprises first electrochemical cell 110 andsecond electrochemical cell 120 as part of a stack with first thermallyconductive solid article portion 131 and second thermally conductivesolid article portion 132, in accordance with certain embodiments. Thethermally conductive solid article portions may comprise alignmentfeatures, as described in more detail below.

Each of the electrochemical cells in the batteries described herein mayhave an electrochemical active region. For example, FIG. 17 shows anembodiment where battery 100 comprises first electrochemical cell 110comprising first electrochemical active region 160 and secondelectrochemical cell 120 comprising second electrochemical active region162. An electrochemical active region refers to a region defined by theoverlap of the anode active surfaces of the anodes and cathode activesurfaces of the cathodes of the electrochemical cell. For example,referring to FIG. 18 , first electrochemical cell 110 haselectrochemical active region 160 defined by the overlap of anode activesurface 166 and cathode active surface 167. As used herein, the term“active surface” is used to describe a surface of an electrode that canbe in physical contact with an electrolyte when the article is part ofan electrochemical cell, and at which electrochemical reactions may takeplace. In some embodiments, a portion of an anode and/or cathode may notbe part of the electrochemical active region of the electrochemicalcell. For example, an anode and cathode may be offset such that aportion of an anode does not overlap with the corresponding cathode,thereby preventing that portion of the anode from participating inelectrochemical reactions with the cathode. Referring to FIG. 18 ,portion 168 of anode 112 does not overlap with any of cathode 114 andtherefore cannot participate in any electrochemical reactions withcathode 114, and therefore portion 118 of anode 112 is not part of firstelectrochemical active region 160, according to certain embodiments.

In some embodiments, an electrochemical cell of the battery (e.g., firstelectrochemical cell, second electrochemical cell) is coupled to anon-planarity of a thermally conductive solid article portion (e.g.,first thermally conductive solid article portion, second thermallyconductive solid article portion) of the battery. FIG. 17 shows onenon-limiting such example, where battery 100 comprises firstelectrochemical cell 110 coupled to non-planarity 161 of first thermallyconductive solid article portion 131 and battery 100 further comprisessecond electrochemical cell 120 coupled to non-planarity 163 of secondthermally conductive solid article portion 132. Any of a variety ofnon-planarities may be part of a thermally conductive solid articleportion and used to couple to an electrochemical cell. For example, anon-planarity of a thermally conductive solid article portion may be adeviation from the mean plane of a surface of the thermally conductivesolid article portion facing the electrochemical cell to which it iscoupled.

As used herein, a surface is said to be “facing” an object when a lineextending normal to and away from the bulk of the material comprisingthe surface intersects the object. For example, a first surface and asecond surface can be facing each other if a line normal to the firstsurface and extending away from the bulk of the material comprising thefirst surface intersects the second surface. A surface can be facinganother object when it is in contact with the other object, or when oneor more intermediate materials are positioned between the surface andthe other object. For example, two surfaces that are facing each othercan be in contact or can include one or more intermediate materialsbetween them. In some instances, a surface and an object (e.g., anothersurface) facing each other are substantially parallel. In someembodiments, two surfaces can be substantially parallel if, for example,the maximum angle defined by the two planes is less than or equal to10°, less than or equal to 5°, less than or equal to 2°, or less than orequal to 1°.

In some embodiments, the non-planarity of a thermally conductive solidarticle portion (e.g., first thermally conductive solid article portion,second thermally conductive solid article portion) of the battery is arecess in the thermally conductive solid article portion. FIG. 17 andFIG. 19 show non-limiting such embodiments. In FIG. 17 , non-planarity161 and non-planarity 163 are recesses in first thermally conductivesolid article portion 131 and second thermally conductive solid articleportion 132, respectively, according to some embodiments. FIG. 19 showsa perspective view schematic diagram of first thermally conductive solidarticle 131 comprising non-planarity 161, which may be a recess in firstthermally conductive solid article 131. A non-planarity (e.g., recess)may have any of a variety of shapes and dimensions, depending, forexample, on the size and shape of a corresponding electrochemical cell(and its electrochemical active region).

An electrochemical cell may be coupled to a recess in a thermallyconductive solid article portion by having a shape such that theelectrochemical cell can fit into the recess. For example, referringagain to FIG. 17 , first electrochemical cell 110 fits intonon-planarity 161 like an object in a pocket such that when firstelectrochemical cell 110 and first thermally conductive solid articleportion 131 are coupled, the position of first electrochemical cell 110is fixed with respect to first thermally conductive solid articleportion 131. It should be understood that while FIG. 17 shows anentirety of the illustrated first electrochemical cell 110 fitting intonon-planarity 161, in some embodiments one or more portions of anelectrochemical cell, such as a conductive tab or pouch, may not be fitinto the non-planarity, and may extend past the thermally conductivesolid article portion.

In some embodiments, the non-planarity of a thermally conductive solidarticle portion (e.g., first thermally conductive solid article portion,second thermally conductive solid article portion) of the battery is aprotrusion. The protrusion may extend away from the main surface of thethermally conductive solid article portion facing the electrochemicalcell. For example, FIG. 20 shows a cross-sectional schematic diagram ofbattery 200 comprising first electrochemical cell 110 coupled tonon-planarity 164 of first thermally conductive solid article portion133 and second electrochemical cell 120 coupled to non-planarity 165 ofsecond thermally conductive solid article portion 134. In FIG. 20 ,non-planarity 164 and non-planarity 165 are protrusions from firstthermally conductive solid article portion 133 and second thermallyconductive solid article portion 134, respectively.

An electrochemical cell may be coupled to a protrusion in a thermallyconductive solid article portion by having a shape such that theelectrochemical cell can fit between protrusions. For example, referringagain to FIG. 20 , first electrochemical cell 110 couples tonon-planarity 164 by fitting between the protrusions of non-planarity164 such that the position of first electrochemical cell 110 is fixedwith respect to first thermally conductive solid article portion 133. Itshould be understood that while FIG. 20 shows an entirety of theillustrated first electrochemical cell 110 fitting between protrusionsof non-planarity 164, in some embodiments one or more portions of anelectrochemical cell, such as a conductive tab or pouch, may not be fitinto or between portions of the non-planarity, and may extend past thethermally conductive solid article portion.

A non-planarity that is protrusion may take any of a variety of forms.For example, in some embodiments, a non-planarity that is a protrusionis a raised edge in the thermally conductive solid article portion(e.g., first thermally conductive solid article portion, secondthermally conductive solid article portion). In some embodiments anon-planarity is a plurality of posts extending from the thermallyconductive solid article portion.

Non-planarities in thermally conductive solid article portions (e.g.,recesses, protrusions) may be formed in any of a variety of suitableways, such as via machining, milling, molding, additive manufacturing(e.g., 3D-printing), etc.

In some embodiments, a thermally conductive solid article portion (e.g.,first thermally conductive solid article portion, second thermallyconductive solid article portion) comprises an alignment feature. Analignment feature may be, for example, a structural component of thethermally conductive solid article portion that can assist with thepositioning of the thermally conductive solid article portion withrespect to another thermally conductive solid article portion of thebattery. In FIG. 17 , first thermally conductive solid article portion131 comprises first alignment feature 137 and second thermallyconductive solid article portion 132 comprises second alignment feature139, according to some embodiments. In some instances, first alignmentfeature 137 and second alignment feature 139 can be used to fix therelative positions of first thermally conductive solid article portion131 and second thermally conductive solid article portion 132 withrespect to each other.

An alignment feature may take any of a variety of suitable structuralforms. For example, in some embodiments, an alignment feature of thethermally conductive solid article portion (e.g., first thermallyconductive solid article portion, second thermally conductive solidarticle portion) is a gap in the thermally conductive solid articleportion. FIG. 17 shows one such example, where first alignment feature137 and second alignment feature 139 are gaps in first thermallyconductive solid article portion 131 and second thermally conductivesolid article portion 132, respectively. FIG. 19 shows a perspectiveview of first alignment feature 137 as a gap in first thermallyconductive solid article portion 131, according to some embodiments. Incertain cases, a gap serving as an alignment feature may be athrough-hole, slot, or opening in a thermally conductive solid articleportion. In some embodiments, an alignment feature of the thermallyconductive solid article portion (e.g., first thermally conductive solidarticle portion, second thermally conductive solid article portion) isan edge of the thermally conductive solid article. For example, whileFIG. 17 shows first alignment feature 137 and second alignment feature139 as gaps, in some embodiments, edge 136 of first thermally conductivesolid article portion 131 and edge 138 of second thermally conductivesolid article portion 132 can be alignment features. In someembodiments, an alignment feature of the thermally conductive solidarticle portion (e.g., first thermally conductive solid article portion,second thermally conductive solid article portion) is a protrusion ofthe thermally conductive solid article. In some embodiments an alignmentfeature of the first thermally conductive solid article portion and analignment feature of the second thermally conductive solid articleportion are substantially similar or the same (e.g., both gaps, bothedges, both protrusions). However, in some instances an alignmentfeature of a first thermally conductive solid article portion and analignment feature of a second thermally conductive solid article portionare different (e.g., a first alignment feature is a gap and a secondalignment feature is a protrusion). In some such cases, a firstalignment feature of a first thermally conductive solid article portionis complementary to a second alignment feature of a second thermallyconductive solid article portion (e.g., a protrusion in one thermallyconductive solid article portion may fit into a recess or through-holeof another thermally conductive solid article portion).

In some embodiments, a thermally conductive solid article portioncomprises multiple alignment features. In certain cases, using multiplealignment features per thermally conductive solid article portion mayfacilitate easier and/or more accurate alignment of components of thebattery. Referring again to FIG. 19 , in some embodiments, firstthermally conductive solid article 131 comprises first alignment feature137 and third alignment feature 237. Each of first alignment feature 137and optional third alignment feature 237 may be substantially alignedwith corresponding alignment features of second thermally conductivesolid article portion 132 during an alignment process. In someembodiments, a thermally conductive solid article portion comprisesmultiple alignment features on the same side of the thermally conductivesolid article portion with respect to an electrochemical cell coupled tothe thermally conductive solid article portion. FIG. 19 shows oneexemplary such embodiment with first alignment feature 137 and thirdalignment feature 237 on the same side of first thermally conductivesolid article 131. Moreover, in some embodiments, the thermallyconductive solid article portion comprises multiple alignment featureson different sides of the thermally conductive solid article portionwith respect to an electrochemical cell coupled to the thermallyconductive solid article portion. FIG. 19 also shows one exemplaryembodiment with first alignment feature 137 and third alignment feature238 on the opposite side of first thermally conductive solid article131. Third alignment feature 238 may be optional, as indicated by thedashed line. In some embodiments, the thermally conductive solid articleportion comprises one or more (e.g., multiple such as two or more)alignment features on the same side of the thermally conductive solidarticle portion with respect to an electrochemical cell coupled to thethermally conductive solid article portion and one or more (e.g.,multiple such as two or more) alignment features on different sides ofthe thermally conductive solid article portion with respect to anelectrochemical cell coupled to the thermally conductive solid articleportion.

Some embodiments comprise substantially aligning a first feature (e.g.,a first alignment feature) of a first thermally conductive solid articleportion with a second feature (e.g., a second alignment feature) of asecond thermally conductive solid article portion. Such an alignmentprocess may result in a first electrochemical active region of a firstelectrochemical cell coupled to a non-planarity of the first thermallyconductive solid article portion being substantially aligned with asecond electrochemical active region of a second electrochemical cellcoupled to a non-planarity of the second thermally conductive solidarticle portion. In certain cases, the first alignment feature and thesecond alignment feature are located such that when the first alignmentfeature is substantially aligned with the second alignment feature, thefirst electrochemical active region and the second electrochemicalactive region are substantially aligned. For example, in FIG. 17 , firstalignment feature 137 and second alignment feature 139 may be located(e.g., with respect to non-planarity 161 and non-planarity 163) suchthat substantial alignment of first alignment feature 137 and secondalignment feature 139 results in the substantial alignment of firstelectrochemical active region 160 with second electrochemical activeregion 162 due to the coupling of first electrochemical cell 110 tonon-planarity 161 and the coupling of second electrochemical cell 120with non-planarity 163. Substantially aligning electrochemical activeareas of electrochemical cells in the battery may result insubstantially uniform conditions for the electrochemical active areas(e.g., during charge and/or discharge). As one example, in someembodiments in which an anisotropic force with a component normal to oneor more of the electrochemical cells is applied, the pressuredistribution experienced by two substantially aligned electrochemicalactive areas may be substantially identical, which can in some caseslead to beneficial performance and/or durability for the battery. Insome embodiments when a first electrochemical active area of the firstelectrochemical cell is substantially aligned with the secondelectrochemical active area of a second electrochemical cell, the firstelectrochemical active area and second electrochemical active area arealigned to within a distance of less than or equal to 2 mm, less than orequal to 1 mm, less than or equal to 0.5 mm, and/or as low as 0.1 mm, orless. In some embodiments when a first electrochemical active area ofthe first electrochemical cell is substantially aligned with the secondelectrochemical active area of a second electrochemical cell, at least90%, at least 95%, at least 98%, at least 99%, at least 99.5% or more ofthe first electrochemical active area overlaps with the secondelectrochemical active area. The extent of alignment may be determined,for example, by visual inspection. Visual inspection in batteries mayinclude discharging and charging the battery and visually examining andcomparing the accumulation of electrode active material (e.g., lithiummetal and/or a lithium metal alloy plating) on electrodes of the firstelectrochemical cell and second electrochemical cell.

One non-limiting way in which alignment features of thermally conductivesolid article portions of the battery may be substantially aligned whenthey are gaps is by passing an object through the alignment features(e.g., through the first alignment feature and the second alignmentfeature). As an example, in FIG. 17 , passing an object through firstalignment feature 137 and second alignment feature 139 along an axisdefined by arrow 170 may substantially align first alignment feature 137and second alignment feature 139. The direction in which the object ispassed through the alignment features may be substantially perpendicularto one or more lateral dimensions of the thermally conductive solidarticle portions (e.g., arrow 170 is substantially perpendicular tolateral dimension 135 of first thermally conductive solid article 131and thermally conductive solid article portion 132 in FIG. 17 ).Exemplary objects that may be passed through the alignment featuresinclude, but are not limited to rods, fasteners, bands, and straps. Anobject passed through the alignment features may be kept in place evenafter alignment (e.g., permanently or removably kept in place), or theobject may be removed following alignment. Another non-limiting way inwhich alignment features of the thermally conductive solid articleportions of the battery may be substantially aligned is by visual oroptical inspection (e.g., to see if electromagnetic radiation can passthrough the alignment features).

Some embodiments may comprise substantially aligning two or morealignment features of the first thermally conductive solid articleportion with two or more features of the second thermally conductivesolid article portion. For example, alignment of components of thebattery may comprise substantially aligning the first alignment featureof the first thermally conductive solid article portion with the secondalignment feature of a second thermally conductive solid article portionand substantially aligning a third alignment feature of the firstthermally conductive solid article portion with a fourth alignmentfeature of the second thermally conductive solid article portion.Aligning multiple alignment features of each thermally conductive solidarticle portion, can, in some cases, increase the accuracy and/or easewith which the components of the battery are aligned.

Another nonlimiting way of aligning features of a battery is by aligningcomponents of the battery with a housing of the battery. For instance,in some embodiments, thermally conductive solid article portions maycomprise alignment features that interlock with features of the housing.For example, an alignment feature such as non-planarity (e.g. a ridge)of a solid housing component of a housing may interlock with alignmentfeatures such as grooves of the thermally conductive solid articleportions. In some embodiments, alignment may be achieved without theincorporation of alignment features, due to geometric constraintsimposed by the housing (e.g., by one or more solid housing componentsdescribed above) on components of the battery. Aligning components ofthe battery with the housing may prove advantageous to some embodimentsby facilitating a reduction in the number of constituent parts of thehousing, reducing a largest lateral pressure applying dimension of thehousing, and/or increasing the battery's volumetric energy density.

In some embodiments, a thermally conductive solid article portion (e.g.,first thermally conductive solid article portion, second thermallyconductive solid article portion) is between electrochemical cells(e.g., first electrochemical cell, second electrochemical cell) in thebattery. FIG. 13A and FIG. 17 show examples of such embodiments, wherefirst thermally conductive solid article portion 131 is between firstelectrochemical cell 110 and second electrochemical cell 120. In certainembodiments, both a first thermally conductive solid article portion anda second thermally conductive solid article portion are between thefirst electrochemical cell and the second electrochemical cell. Forexample, referring again to FIG. 13A and FIG. 17 , first thermallyconductive solid article portion 131 is between first electrochemicalcell 110 and second electrochemical cell 120, and second thermallyconductive solid article portion 132 is between first thermallyconductive solid article portion 131 and second electrochemical cell120. In some embodiments, a thermally insulating compressible solidarticle portion is between the first thermally conductive solid articleportion and the second thermally conductive solid article portion. FIG.21 shows one such embodiment, where thermally insulating compressiblesolid article portion 140 of exemplary battery 300 is between firstthermally conductive solid article portion 131 and second thermallyconductive solid article portion 132.

In some embodiments, the first thermally conductive solid articleportion and the second thermally conductive solid article portion arepart of discrete articles. Referring again to FIG. 13A, in someembodiments first thermally conductive solid article portion 131 andsecond thermally conductive solid article portion 132 are separate,discrete articles (e.g., separate sheets or fins). However, in someembodiments, first thermally conductive solid article portion and thesecond thermally conductive solid article portion are part of the samearticle. For example, first thermally conductive solid article portion131 and second thermally conductive solid article portion 132 may beconnected via a third thermally conductive solid article portion (notpictured) in FIG. 13A. As one example, the battery may comprise athermally conductive solid article that is foldable and/or has aserpentine shape such that electrochemical cells and/or other componentsof the battery can be arranged between portions of the thermallyconductive solid article.

In some aspects, batteries comprising solid articles that can compensatefor dimensional changes of other battery components while also limitingheat transfer between electrochemical cells are generally described.FIG. 22 is a schematic diagram of a non-limiting embodiment of battery100. Battery 100 in FIG. 22 comprises first electrochemical cell 110 andsecond electrochemical cell 120 as part of a stack with thermallyinsulating compressible solid article portion 140. In some, but notnecessarily all cases, the thermally insulating compressible solidarticle portion is in direct contact with the first electrochemical celland/or the second electrochemical cell. For example, in FIG. 22 ,thermally insulating compressible solid article portion 140 is shown asbeing in direct contact with both first electrochemical cell 110 andsecond electrochemical cell 120. However, direct contact is notrequired, and in some embodiments there are one or more interveningcomponents (e.g., other solid article portions such as plates or fins,sensors, etc.) between the thermally insulating compressible solidarticle portion and the first electrochemical cell and/or secondelectrochemical cell.

The thermally insulating compressible solid article portion may take anyof a variety forms. For example, the thermally insulating compressiblesolid article portion may be in the form of a solid block, a foam sheet,a mesh, or any other suitable form, provided that it be thermallyinsulating and compressible. It should be understood that while thethermally insulating compressible solid article portion is referred toas a solid article, it may be at least partially hollow and/or containpores or voids.

In some embodiments, the thermally insulating compressible solid articleportion is a unitary object. FIG. 22 depicts thermally insulatingcompressible solid article portion 140 as a unitary object (e.g., asingle sheet of foam), as one example. It should be understood that athermally insulating compressible solid article portion that is aunitary object may be part of a larger article in some instances. Insome embodiments, the thermally insulating compressible solid articleportion comprises multiple separate objects. For example, the thermallyinsulating compressible solid article portion may comprise multiplelayers (e.g., sheets) of either the same or different materials (e.g.,foams) as a stack or otherwise arranged. For the properties describedherein (e.g., uncompressed thickness, compression set, compressivestress versus percent compression, thermal conductivity, etc.), themeasured values correspond to the entirety of the thermally insulatingcompressible solid article portion. For example, if the thermallyinsulating compressible solid article portion is a unitary object, theparameters correspond to that unitary object. In instances where thethermally insulating compressible solid article portion comprisesmultiple separate objects (e.g., a stack of foam sheets), the parametersof the thermally insulating compressible solid article portioncorrespond to that of the aggregate of all the separate objects of thatportion (e.g., all foam sheets measured together as a stack).

In some embodiments, the thermally insulating compressible solid articleportion comprises a foam. A foam solid article generally refers to asolid containing pockets of (“cells”) capable of being occupied by afluid. The pockets may be present throughout the dimensions of thesolid. The foam may be present as a relatively high percentage of thethermally insulating compressible solid article portion (e.g., greaterthan or equal to 50 weight percent (wt %), greater than or equal to 75wt %, greater than or equal to 90 wt %, greater than or equal to 95 wt%, greater than or equal to 99 wt %, or more). The use of thermallyinsulating compressible solid article portions comprising a relativelylarge amount of foam may, in some cases, contribute to a relatively highcompressibility of the thermally insulating compressible solid articleportion. For example, referring back to FIG. 13A or FIG. 22 , in certainembodiments in which thermally insulating compressible solid articleportion 140 has a relatively high foam content, pressure experienced bybattery 100 may result in a relatively large compression of thermallyinsulating compressible solid article portion 140.

In some embodiments, the thermally insulating compressible solid articleportion is or comprises a closed-cell foam. A closed-cell foam solidgenerally refers to a foam comprising cells (gas pockets) that arediscrete and completely surrounded by the solid material of the foam.FIG. 23A shows one such example, where thermally insulating compressiblesolid article portion 140 a of battery 100 a is a closed-cell foamcomprising discrete cells 145 a.

However, in some embodiments, the thermally insulating compressiblesolid article portion is or comprises an open-cell foam. An open-cellfoam solid generally refers to a foam comprising cells connected to eachother, thereby allowing for a gas or other fluid to travel from cell tocell. FIG. 23B shows one such example, where thermally insulatingcompressible solid article portion 140 b of battery 100 b is anopen-cell foam comprising connected cells 145 b.

In some embodiments, thermally insulating compressible solid articleportion 140 comprises a microcellular foam. A microcellular foamgenerally refers to a foam whose cells have an average largestcross-sectional dimension on the order of microns (e.g., greater than orequal to 0.1 micron, greater than or equal to 1 micron, and/or up to 50microns, up to 100 microns, or up to 500 microns). For example, inembodiments in which thermally insulating compressible solid articleportion 140 in FIG. 23A is a microcellular foam, cell 145 a may have alargest cross-sectional dimension of between 0.1 and 500 microns.Microcellular foams are typically made of polymeric materials (e.g.,plastics) and can be prepared, for example by dissolving gases underhigh pressure into the material from which the foam is made. Foams suchas microcellular foams may be useful in some instances in whichthermally insulating compressible solid article portions having arelatively low mass density are desired. A low-density thermallyinsulating compressible solid article portion may contribute at least inpart to a battery having a high specific energy density. In someembodiments, the density of the thermally-insulating compressible solidarticle portion is variable. For example, in some embodiments, regionsoccupying at least 0.5%, at least 1%, at least 2%, at least 5%, at least10%, or more of the external geometric volume of the thermallyinsulating compressible solid article portion have a density (massdensity) that is at least 5%, at least 10%, at least 25%, at least 50%,at least 75%, at least 90%, at least 95%, or at least 99% lower than anoverall average density of the thermally insulating compressible solidarticle portion (which can be calculating by dividing the mass of theoverall thermally insulating compressible solid article by the overalluncompressed volume of the thermally insulating compressible solidarticle). One non-limiting way of achieving such variance in density isby including holes/gaps in the thermally insulating compressible articleportion such that the overall external geometric dimensions of thethermally insulating solid article portion are suitable for performingsome or all of the roles described herein, while a mass of the thermallyinsulating compressible solid article is reduced. It has been observedthat some such configurations may provide for a relative reduction inthe mass of the battery (and an increase in energy density) withoutsignificantly affecting performance of the battery. Further, it has alsobeen observed that some such configurations may provide for relativelyuniform pressure distribution experienced by one or more electrochemicalcells of the battery is relatively uniform, at least because the densityof region of a thermally compressible solid article may affect amagnitude of force experienced by an electrochemical cell adjacent tothat region.

In some embodiments, the thermally insulating compressible solid articleportion comprises a mesh. As an example, in certain instances, thethermally insulating compressible solid article portion is a meshstructure made of strands of flexible, thermally-insulating material(e.g., fiber, plastic) that are attached and/or woven together.

In some embodiments, the thermally insulating compressible solid articleportion is porous. As one example, referring again to FIGS. 13A-13B andFIG. 22 , thermally insulating compressible solid article portion 140 ismade of a porous material. As used herein, a “pore” refers to a pore asmeasured using ASTM Standard Test D4284-07, and generally refers to aconduit, void, or passageway, at least a portion of which is surroundedby the medium in which the pore is formed such that a continuous loopmay be drawn around the pore while remaining within the medium.Generally, voids within a material that are completely surrounded by thematerial (and thus, not accessible from outside the material, e.g.,closed cells) are not considered pores within this context. As such, athermally insulating compressible solid article portion may be orcomprise an open-cell solid, such an open-cell solid foam. It should beunderstood that, in cases where the thermally insulating compressiblesolid article portion comprises an agglomeration of particles, poresinclude both the interparticle pores (i.e., those pores defined betweenparticles when they are packed together, e.g., interstices) andintraparticle pores (i.e., those pores lying within the envelopes of theindividual particles). Pores may comprise any suitable cross-sectionalshape such as, for example, circular, elliptical, polygonal (e.g.,rectangular, triangular, etc.), irregular, and the like.

The porosity of a component of a battery (e.g., the thermally insulatingcompressible solid article portion comprising open cells) may bemeasured by physically separating the different regions of theelectrochemical device by, for example, cutting out a region of thecomponent, and then measuring the separated portion using theabove-referenced ASTM Standard Test D4284-07.

In some instances, the thermally insulating compressible solid articleportion (e.g., comprising an open-cell solid such as an open-cell foam)has a relatively high porosity. Having a relatively high porosity maycontribute to the thermally insulating compressible solid articleportion having a relatively low density, which in some instances can beadvantageous as described above. A high porosity may also contribute, insome cases, to a relatively high compressibility. In some embodiments,the thermally insulating compressible solid article portion has aporosity of greater than or equal to 40%, greater than or equal to 50%,greater than or equal to 60%, or higher by volume. In some embodiments,the thermally insulating compressible solid article portion has aporosity of less than or equal to 90%, less than or equal to 80%, lessthan or equal to 70%, or less by volume. Combinations of these rangesare possible. For example, in some cases, the thermally insulatingcompressible solid article portion has a porosity of greater than orequal to 40% and less than or equal to 90%.

The thermally insulating compressible solid article portion may have anyof a variety of suitable pore sizes, depending on, for example, thechoice of material for the compressible solid article portion or themagnitude of force to be applied to the battery. For example, in somecases, the thermally insulating compressible solid article portion hasan average pore size of greater than or equal to 0.1 microns, greaterthan or equal to 0.5 microns, greater than or equal to one micron,greater than or equal to 10 microns, greater than or equal to 50microns, or greater. In some cases, the thermally insulatingcompressible solid article portion has an average pore size of less thanor equal to 1 mm, less than or equal to 500 microns, less than or equalto 100 microns, or less. Combinations of these ranges are possible. Forexample, in some embodiments, the thermally insulating compressiblesolid article portion has an average pore size of greater than or equalto 0.1 microns and less than or equal to 1 mm, or greater than or equalto 1 micron and less than or equal to 100 microns.

In some embodiments, the thermally insulating compressible solid articleportion has a relatively high void percentage. The voids of a solidobject in this context generally refers to portions of the solids objectnot occupied by solid material. Voids may be occupied by a fluid such asa gas (e.g., air) or a liquid. It should be understood that pores suchas open-cells may contribute to the void percentage, and closed-cellsmay also contribute to void percentage. As such, a thermally insulatingcompressible solid article portion comprising closed cells (e.g., aclosed-cell foam such as thermally insulating compressible solid articleportion 140 a in FIG. 23A) may have a relatively high void percentage.Void percentage a solid article may be determined by dividing the voidvolume of the article by the volume defined by the outer boundaries ofthe article. Having a relatively high void percentage may contribute tothe thermally insulating compressible solid article portion having arelatively low density, which in some instances can be advantageous asdescribed above. A high void percentage may also contribute, in somecases, to a relatively high compressibility. In some embodiments, thethermally insulating compressible solid article portion has a voidpercentage of greater than or equal to 25%, greater than or equal to40%, greater than or equal to 50%, and/or up to 60%, up to 75%, up to90%, or more.

As a thermal insulator, the thermally insulating compressible solidarticle portion may contribute at least in part to advantageous thermalmanagement of components of the battery. In some embodiments, thethermally insulating compressible solid article portion has a relativelylow effective thermal conductivity (consequently making it a relativelygood thermal insulator). The thermal insulating capability of thethermally insulating compressible solid article portion can, in somecases, contribute at least in part to thermally isolating one or moreelectrochemical cells and the battery from one or more other portions ofthe battery. For example, referring back to FIGS. 13A-13B and FIG. 22 ,in some embodiments in which thermally insulating compressible solidarticle portion 140 has a relatively low effective thermal conductivity,thermally insulating compressible solid article portion 140 mitigatesheat transfer between first electrochemical cell 110 and secondelectrochemical cell 120. Such a mitigation in heat transfer can, insome instances, reduce propagation of deleterious phenomena among theelectrochemical cells (e.g., during cycling).

In some embodiments, the thermally insulating compressible solid articleportion has a relatively low effective thermal conductivity in thethickness direction. Referring again to FIG. 22 , for example, thermallyinsulating compressible solid article portion 140 may have a loweffective thermal conductivity in thickness direction 143. As a result,thermally insulating compressible solid article portion 140 may reducethe rate at which heat is transferred from first electrochemical cell110, through thermally insulating compressible solid article portion 140in thickness direction 143, and to second electrochemical cell 120,according to certain embodiments. This reduced extent of heat transferin the thickness direction can, in some instances, improve the safetyand performance of the battery (e.g., by reducing thermal propagation).In some embodiments, the thermally insulating compressible solid articleportion has an effective thermal conductivity of less than or equal to0.5 W m⁻¹ K⁻¹, less than or equal to 0.25 W m⁻¹ K⁻¹, and/or as low as0.1 W m⁻¹ K⁻¹, as low as 0.01 W m⁻¹ K⁻¹, or less in the thicknessdirection at a temperature of 25° C. For example, the thermallyinsulating compressible solid article portion may comprise amicrocellular foam and have an effective thermal conductivity of 0.21 Wm⁻¹ K⁻¹ in the thickness direction at a temperature of 25° C. In someembodiments, the rate of heat transfer between two components of thebattery (e.g., first electrochemical cell 110 and second electrochemicalcell 120 in FIG. 22 ) is relatively low. In certain cases, the rate ofheat transfer from the first electrochemical cell to the secondelectrochemical cell is less than or equal to 5 W m⁻¹ K⁻¹, less than orequal to 2.5 W m⁻¹ K⁻¹, and/or as low as 1 W m⁻¹ K⁻¹, as low as 0.1 Wm⁻¹ K⁻¹, or less when the temperature difference between the firstelectrochemical cell and the second electrochemical cell is 10 K.

The compressibility of the thermally insulating compressible solidarticle portion may be useful in any of a variety of applications. Asone example, in some instances in which one or more components of thebattery change dimension during a charging and/or discharge process, aresulting compression of the thermally insulating compressible solidarticle portion may compensate for that change in dimension. In somesuch cases, the compressibility of the thermally insulating compressiblesolid article portion under stress may reduce the extent to which abattery expands or contracts when electrochemical cells within thebattery undergo expansion and/or contraction during cycling.

FIGS. 24A-24B show cross-sectional schematic diagrams of battery 100 inthe absence (FIG. 24A) and presence (FIG. 24B) of an anisotropic forcein the direction of arrow 481, with a component 482 normal to anelectrochemical cell. The anisotropic force in the direction of arrow481 may also have a component 484 parallel to an electrochemical cell.As described above, in some cases, at least a portion of the anisotropicforce is applied by a pressure device such as solid plate (e.g., anendplate). In some instances, at least a portion of the anisotropicforce is caused by a change in dimension (e.g., expansion) of one ormore components of the battery. For example, in some cases a chargingprocess of the battery causes one or more electrochemical cells (e.g.,the first electrochemical cell, the second electrochemical cell) toexpand in a thickness direction. One such example is in certain caseswhere a lithium metal and/or a lithium metal alloy is used as an anodeactive material, and lithium deposition on the anode occurs duringcharging.

In some embodiments, the application of force to the thermallyinsulating compressible solid article portion (e.g., via the firstelectrochemical cell and/or the second electrochemical cell or anintervening battery component) causes the thermally insulatingcompressible solid article portion to compress in the thicknessdirection. Referring again to FIGS. 24A-24B, for example, thermallyinsulating compressible solid article portion 140 may have uncompressedthickness 146 in the absence of an applied anisotropic force (as shownin FIG. 24A) and smaller compressed thickness 147 when anisotropic force481 is applied and/or when expansion of first electrochemical cell 110and/or second electrochemical cell 120 occurs.

In some embodiments, the thermally insulating compressible solid articleportion has a relatively low compression set. The compression set of anarticle generally refers to the amount of permanent (plastic)deformation that occurs when the article is compressed to a givendeformation, for a given amount of time, at a given temperature.Compression set of an article can be measured, for example using ASTMD395. For elastomeric materials, having a low compression set isassociated with an ability for the material to maintain elasticproperties even after prolonged compressive stress. Having a relativelylow compression set may be beneficial, in some cases, where it isdesired that the thermally insulating compressible solid article portionbe able to regain at least a portion of its thickness when an appliedcompressive stress is removed. As an example, in some cases where thethermally insulating compressible solid article portion is compresseddue to an expansion of an electrochemical cell in the battery, asubsequent contraction of the electrochemical cell may reduce thecompressive stress applied. Having a relatively low compression set maythen allow the thermally insulating compressible solid article to expandin thickness as the electrochemical cell contracts, thereby compensatingfor the change in dimension. In some embodiments, the thermallyinsulating compressible solid article portion has a compression set ofless than or equal 15%, less than or equal to 12%, or less. In someembodiments, the thermally insulating compressible solid article portionhas a compression set of less than or equal to 10%, less than or equalto 5%, or less. In some embodiments, the thermally insulatingcompressible solid article portion has a compression set of greater thanor equal to 1%, greater than or equal to 2%, or more. Combinations ofthese ranges are possible. For example, in some embodiments, thethermally insulating compressible solid article portion has acompression set of greater than or equal to 1% and less than or equal to10%. In some embodiments, the thermally insulating compressible solidarticle portion has a compression set value in one of the ranges abovedetermined using a constant force measurement (e.g., ASTM D395 TestMethod A). In some embodiments, the thermally insulating compressiblesolid article portion has a compression set value in one of the rangesabove determined using a constant displacement measurement (e.g., ASTMD395 Test Method B).

In some embodiments, the thermally insulating compressible solid articleportion has a relatively high compressibility. The compressibility of anarticle generally refers to the relative dimensional change of anarticle as a response to a change in compressive stress. In someinstances, for example, the change in thickness 147 relative tothickness 146 in FIGS. 24A-24B is relatively large for a given magnitudeof compressive stress (e.g., when the force from arrow 481 is applied).In some embodiments, at a compressive stress of 12 kgf/cm², the percentcompression of the thermally insulating compressible solid articleportion is at least 30%, and at a compressive stress of 40 kgf/cm², thepercent compression of the thermally insulating compressible solidarticle portion is at least 80%. In some embodiments, at a compressivestress of 12 kgf/cm², the percent compression of the thermallyinsulating compressible solid article portion is at least 30%, and at acompressive stress of 40 kgf/cm², the percent compression of thethermally insulating compressible solid article portion is at least 50%.

The compressive response of a thermally insulating compressible solidarticle portion may be considered as a compressive stress versus percentcompression curve. The thermally insulating compressible solid articleportion may have a compressive stress versus percent compression curvethat is suitable for a battery in which a high magnitude of anisotropicforce with a component normal to one or more of the electrochemicalcells is applied. In some instances, the thermally insulatingcompressible solid article portion has a compressive stress versuspercent compression curve that is suitable for a battery in which one ormore electrochemical cell undergoes a relatively high change indimension during charging and discharging (e.g., such as certainelectrochemical cells comprising lithium metal and/or lithium metalanode active materials).

In some such embodiments, the thermally insulating compressible solidarticle has a compressive stress versus percent compression curve in thehatched region of FIG. 25 . It should be understood that a curve isconsidered to be in the hatched region if it is in the interior of thehatched region or at a boundary of the hatched region. In someembodiments, at least 50%, at least 75%, at least 90%, or more of thex-axis values of the compressive stress versus percent compression curveof the thermally insulating compressible solid article portion is in thehatched region. For example, if a compressive stress versus percentcompression curve is measured for a sample for 100 equally spacedcompression values between 0% and 80% (i.e., x-axis increments of 0.8%),and the measured compressive stress falls within the hatched region ofFIG. 25 for at least 50 of the 100 compression values measured, then atleast 50% of the x-axis value of the compressive stress versus percentcompression curve of that sample is in the hatched region. In someembodiments, the thermally insulating compressible solid article has acompressive stress versus percent compression curve in the hatchedregion of FIG. 25 for x-axis values of greater than or equal to 1%,greater than or equal to 10%, greater than or equal to 20%, greater thanor equal to 30%, greater than or equal to 40%, and/or up to 50%, up to60%, up to 80%, or greater. Combinations of these ranges (e.g., x-axisvalues of greater than or equal to 1% and less than or equal to 80% orgreater than or equal to 30% and less than or equal to 50%) arepossible. Properties that may affect the compressive stress versuspercent compression curve of a thermally insulating compressible solidarticle portion include intrinsic properties (e.g., uncompresseddensity) and extrinsic properties (e.g., thickness).

The measurement of the compressive stress versus percent compressioncurve (as shown in FIG. 25 ) of a sample may be conducted as follows.The compression rate may be, for example, greater than or equal to 0.001mm/s, greater than or equal to 0.05, and/or up to 0.1 mm/s using amodified version of ASTM D3574.

In some embodiments, the thermally insulating compressible solid articleportion has a relatively high resilience. The resilience of an articlegenerally refers to the percentage of energy released when a deformedobject recovers from deformation relative to the energy required toproduce the deformation. Resilience can be measured, for example, usingASTM D3574 Test H (a ball drop resilience measurement). A relativelyhigh resilience may contribute to the thermally insulating compressiblesolid article portion being durable under multiple repeated compressionsand decompression of the battery (e.g., during charging anddischarging). In some embodiments, the thermally insulating compressiblesolid article portion has a resilience of at least 60%, at least 65%, atleast 75%, at least 90%, at least 95%, or more. In some embodiments, thethermally insulating compressible solid article portion has both arelatively high compressibility and a relatively high resilience (e.g.,with values in the ranges described above), which may contribute to ahigh extent of compensation of dimensional changes in the battery whilealso being durable.

In some embodiments, the thermally insulating compressible solid articleportion has a relatively high dynamic continuous load limit. A dynamiccontinuous load limit generally refers to the maximum compressive stressapplied to the article before failure occurs. Having a relatively highdynamic continuous load limit may be useful in some embodiments where arelatively high magnitude of anisotropic force with a component normalto one or more electrochemical cells of the battery is applied, or whereone or more of the electrochemical cells undergoes a relatively largeexpansion during cycling. In some embodiments, the thermally insulatingcompressible solid article portion has a dynamic continuous load limitof greater than or equal to 30 kgf/cm², greater than or equal to 35kgf/cm², greater than or equal to 40 kgf/cm², and/or up to 45 kgf/cm²,or greater.

In some embodiments, the thermally insulating compressible solid articleportion has a relatively low uncompressed mass density. A low massdensity may contribute, at least in part, to the battery having arelatively high specific energy density. The uncompressed mass densityof the thermally insulating compressible solid article portion refers tothe bulk mass per unit volume of the article portion in the absence of aload (e.g., compressive stress). In some embodiments, the thermallyinsulating compressible solid article portion has an uncompressed massdensity of greater than or equal to 0.3 g/cm³, greater than or equal to0.35 g/cm³, greater than or equal to 0.4 g/cm³, greater than or equal to0.45 g/cm³, greater than or equal to 0.5 g/cm³, and/or up to 0.55 g/cm³,up to 0.6 g/cm³, up to 0.65 g/cm³, up to 0.7 g/cm³, or greater at 25° C.

The thermally insulating compressible solid article portion can be madeof any of a variety of suitable materials, provided that it have one ormore of the combinations of thermal and mechanical properties in thepresent disclosure. In some embodiments, the thermally insulatingcompressible solid article portion comprises a polymeric material. Arelatively large percentage of the thermally insulating compressiblesolid article portion may be made of a polymeric material. For example,greater than or equal to 50 wt %, greater than or equal to 75 wt %,greater than or equal to 90 wt %, greater than or equal to 95 wt %,greater than or equal to 99 wt %, or more (e.g., 100 wt %) of thethermally insulating compressible solid article portion may be made of apolymeric material. In certain embodiments, the thermally insulatingcompressible solid article portion comprises a polymeric foam, such as amicrocellular polymeric foam.

While any of a variety of polymeric materials may be suitable, incertain instances the thermally insulating compressible solid articleportion comprises a relatively elastic polymer. In some embodiments, thethermally insulating compressible solid article portion is or comprisesan elastomer. As one non-limiting example, the thermally insulatingcompressible solid article portion may comprise a polyurethane.Polyurethanes are polymers comprising organic repeat units linked bycarbamate (urethane) units. Polyurethanes can be made using any of avariety of techniques, such as by reacting isocyanates and polyols. Insome embodiments, the thermally insulating compressible solid articleportion is or comprises a microcellular polyurethane foam (e.g., foamsheet or foam layer). Referring to FIG. 22 , for example, battery 100may comprise first electrochemical cell 110, second electrochemical cell120, and thermally insulating compressible solid article portion 140between first electrochemical cell 110 and second electrochemical cell120, where thermally insulating compressible solid article portion 140is an elastomeric microcellular foam layer or sheet made ofpolyurethane. One non-limiting example of an elastomeric microcellularpolyurethane foam that can be used as a thermally insulatingcompressible solid article portion is sold by BASF under the trade nameCellasto®.

The thermally insulating compressible solid article may have a thicknessas well as two orthogonal lateral dimensions that are orthogonal to eachother as well as orthogonal to the thickness. For example, referring toFIG. 24A, thermally insulating compressible solid article portion 140has thickness 146, lateral dimension 141, and a second lateral dimension(not pictured) orthogonal to both thickness 146 and lateral dimension141 (which would run into and out of the plane of the drawing in FIG.24A). As mentioned above, the thermally insulating compressible solidarticle may have an uncompressed thickness (e.g., uncompressed thickness146 in FIG. 24A) and a compressed thickness (e.g., compressed thickness147 FIG. 24B), with the latter depending in some cases on the magnitudeof an applied force.

The dimensions of the thermally insulating compressible solid articleportion may be chosen based on any of a variety of considerations. Forexample, the thickness (e.g., uncompressed thickness) or lateraldimensions may be chosen based on the desired total size of the batteryand/or a desired pack burden (defined as one minus the mass of theelectrochemical cells of the battery divided by the total mass of thebattery). In some embodiments, the uncompressed thickness of thethermally insulating compressible solid article portion is such that asufficient amount of compression can occur (e.g., to compensate forexpansion of the first electrochemical cell and/or secondelectrochemical cell during cycling).

In some embodiments, the thermally insulating compressible solid articleportion has an uncompressed thickness of greater than or equal to 2 mm,greater than or equal to 3 mm, greater than or equal to 4 mm, greaterthan or equal to 5 mm, greater than or equal to 5.5 mm, greater than orequal to 6 mm, or greater. In some embodiments, the thermally insulatingcompressible solid article portion has an uncompressed thickness of lessthan or equal to 10 mm, less than or equal to 9 mm, less than or equalto 7 mm, or less. Combinations of these ranges are possible. Forexample, in some embodiments, the thermally insulating compressiblesolid article portion has an uncompressed thickness of greater than orequal to 2 mm and less than or equal to 10 mm, or greater than or equalto 5.5 mm and less than or equal to 6 mm.

In some embodiments the thermally insulating compressible solid articleportion has one or more lateral dimension of greater than or equal to 50mm, greater than or equal to 65 mm, greater than or equal to 80 mm,and/or up to 90 mm, up to 100 mm, up to 200 mm, or more. In someembodiments, the thermally insulating compressible solid article portionhas at least one lateral dimension that is at least 5 times, at least 10times, and/or up to 20 times, up to 50 times, up to 100 times or moregreater than the uncompressed thickness of the thermally insulatingcompressible solid article portion.

In some embodiments, the battery has more than one thermally insulatingcompressible solid article portion. For example, in some embodiments,the battery comprises a third electrochemical cell, and a secondthermally insulating compressible solid article portion between thesecond electrochemical cell and the third electrochemical cell. FIG. 26shows a cross-sectional schematic diagram of one such embodiment, wherebattery 600 comprises, in order: first electrochemical cell 110, firstthermally insulating compressible solid article portion 140, secondelectrochemical cell 120, second thermally insulating compressible solidarticle portion 240, and third electrochemical cell 210. It should beunderstood that the battery may not be limited to three electrochemicalcells, and may comprise at least 1, at least 2, at least 3, at least 5,at least 8, at least 10, and/or up to 12, up to 15, up to 20, up to 24,up to 30 or more electrochemical cells. In some such cases, the totalnumber of thermally insulating compressible solid article portions isequal to one more than the total number of electrochemical cells in thebattery (e.g., 12 electrochemical cells and 13 thermally insulatingcompressible solid article portions). For example, there may be anelectrochemical cell between each of the thermally insulatingcompressible solid article portions.

In some embodiments, the first thermally insulating compressible solidarticle portion and the second thermally insulating compressible solidarticle portion are part of discrete articles. Referring again to FIG.26 , in some embodiments first thermally insulating compressible solidarticle portion 140 and second thermally insulating compressible solidarticle portion 240 are separate, discrete articles (e.g., separate foamsheets). However, in some embodiments, the first thermally insulatingcompressible solid article portion and the second thermally insulatingcompressible solid article portion are part of the same article. Forexample, first thermally insulating compressible solid article portion140 and second thermally insulating compressible solid article portion240 may be connected via a third thermally insulating compressible solidarticle portion hidden behind second electrochemical cell 120 in FIG. 26. As one example, the battery may comprise a thermally insulatingcompressible solid article that is foldable and/or has a serpentineshape such that electrochemical cells and/or other components of thebattery can be arranged between portions of the thermally insulatingcompressible solid article.

A variety of anode active materials are suitable for use with the anodesof the electrochemical cells described herein, according to certainembodiments. In some embodiments, the anode active material compriseslithium (e.g., lithium metal), such as lithium foil, lithium depositedonto a conductive substrate or onto a non-conductive substrate (e.g., arelease layer), and lithium alloys (e.g., lithium-aluminum alloys andlithium-tin alloys). Lithium can be contained as one film or as severalfilms, optionally separated. Suitable lithium alloys for use in theaspects described herein can include alloys of lithium and aluminum,magnesium, silicium (silicon), indium, and/or tin. In some embodiments,the anode active material comprises lithium (e.g., lithium metal and/ora lithium metal alloy) during at least a portion of or during all of acharging and/or discharging process of the electrochemical cell. In someembodiments, the anode active material comprises during a portion of acharging and/or discharging process of the electrochemical cell, but isfree of lithium metal and/or a lithium metal alloy at a completion of adischarging process.

In some embodiments, the anode active material contains at least 50 wt %lithium. In some cases, the anode active material contains at least 75wt %, at least 90 wt %, at least 95 wt %, or at least 99 wt % lithium.

In some embodiments, the anode is an electrode from which lithium ionsare liberated during discharge and into which the lithium ions areintegrated (e.g., intercalated) during charge. In some embodiments, theanode active material is a lithium intercalation compound (e.g., acompound that is capable of reversibly inserting lithium ions at latticesites and/or interstitial sites). In some embodiments, the anode activematerial comprises carbon. In certain cases, the anode active materialis or comprises a graphitic material (e.g., graphite). A graphiticmaterial generally refers to a material that comprises a plurality oflayers of graphene (i.e., layers comprising carbon atoms covalentlybonded in a hexagonal lattice). Adjacent graphene layers are typicallyattracted to each other via van der Waals forces, although covalentbonds may be present between one or more sheets in some cases. In somecases, the carbon-comprising anode active material is or comprises coke(e.g., petroleum coke). In certain embodiments, the anode activematerial comprises silicon, lithium, and/or any alloys of combinationsthereof. In certain embodiments, the anode active material compriseslithium titanate (Li₄Ti₅O₁₂, also referred to as “LTO”), tin-cobaltoxide, or any combinations thereof.

A variety of cathode active materials are suitable for use with cathodesof the electrochemical cells described herein, according to certainembodiments. In some embodiments, the cathode active material comprisesa lithium intercalation compound (e.g., a compound that is capable ofreversibly inserting lithium ions at lattice sites and/or interstitialsites). In certain cases, the cathode active material comprises alayered oxide. A layered oxide generally refers to an oxide having alamellar structure (e.g., a plurality of sheets, or layers, stacked uponeach other). Non-limiting examples of suitable layered oxides includelithium cobalt oxide (LiCoO₂), lithium nickel oxide (LiNiO₂), andlithium manganese oxide (LiMnO₂). In some embodiments, the layered oxideis lithium nickel manganese cobalt oxide (LiNi_(x)Mn_(y)Co_(z)O₂, alsoreferred to as “NMC” or “NCM”). In some such embodiments, the sum of x,y, and z is 1. For example, a non-limiting example of a suitable NMCcompound is LiNi_(1/3)Mn_(1/3)Co_(1/3)O₂. In some embodiments, a layeredoxide may have the formula (Li₂MnO₃)_(x)(LiMO₂)_((1-x)) where M is oneor more of Ni, Mn, and Co. For example, the layered oxide may be(Li₂MnO₃)_(0.25)(LiNi_(0.3)Co_(0.15)Mn_(0.55)O₂)_(0.75). In someembodiments, the layered oxide is lithium nickel cobalt aluminum oxide(LiNi_(x)Co_(y)Al_(z)O₂, also referred to as “NCA”). In some suchembodiments, the sum of x, y, and z is 1. For example, a non-limitingexample of a suitable NCA compound is LiNi_(0.8)Co_(0.15)Al_(0.05)O₂. Incertain embodiments, the cathode active material is a transition metalpolyanion oxide (e.g., a compound comprising a transition metal, anoxygen, and/or an anion having a charge with an absolute value greaterthan 1). A non-limiting example of a suitable transition metal polyanionoxide is lithium iron phosphate (LiFePO₄, also referred to as “LFP”).Another non-limiting example of a suitable transition metal polyanionoxide is lithium manganese iron phosphate (LiMn_(x)Fe_(1-x)PO₄, alsoreferred to as “LMFP”). A non-limiting example of a suitable LMFPcompound is LiMn_(0.8)Fe_(0.2)PO₄. In some embodiments, the cathodeactive material is a spinel (e.g., a compound having the structureAB₂O₄, where A can be Li, Mg, Fe, Mn, Zn, Cu, Ni, Ti, or Si, and B canbe Al, Fe, Cr, Mn, or V). A non-limiting example of a suitable spinel isa lithium manganese oxide with the chemical formula LiM_(x)Mn_(2-x)O₄where M is one or more of Co, Mg, Cr, Ni, Fe, Ti, and Zn. In someembodiments, x may equal 0 and the spinel may be lithium manganese oxide(LiMn₂O₄, also referred to as “LMO”). Another non-limiting example islithium manganese nickel oxide (LiNi_(x)M_(2-x)O₄, also referred to as“LMNO”). A non-limiting example of a suitable LMNO compound isLiNi_(0.5)Mn_(1.5)O₄. In certain cases, the electroactive material ofthe second electrode comprises Li_(1.14)Mn_(0.42)Ni_(0.25)Co_(0.29)O₂(“HC-MNC”), lithium carbonate (Li₂CO₃), lithium carbides (e.g., Li₂C₂,Li₄C, Li₆C₂, Li₈C₃, Li₆C₃, Li₄C₃, Li₄C₅), vanadium oxides (e.g., V₂O₅,V₂O₃, V₆O₁₃), and/or vanadium phosphates (e.g., lithium vanadiumphosphates, such as Li₃V₂(PO₄)₃), or any combination thereof.

In some embodiments, the cathode active material comprises a conversioncompound. For instance, the cathode may be a lithium conversion cathode.It has been recognized that a cathode comprising a conversion compoundmay have a relatively large specific capacity. Without wishing to bebound by a particular theory, a relatively large specific capacity maybe achieved by utilizing all possible oxidation states of a compoundthrough a conversion reaction in which more than one electron transfertakes place per transition metal (e.g., compared to 0.1-1 electrontransfer in intercalation compounds). Suitable conversion compoundsinclude, but are not limited to, transition metal oxides (e.g., Co₃O₄),transition metal hydrides, transition metal sulfides, transition metalnitrides, and transition metal fluorides (e.g., CuF₂, FeF₂, FeF₃). Atransition metal generally refers to an element whose atom has apartially filled d sub-shell (e.g., Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu,Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Os, Ir, Pt,Au, Hg, Rf, Db, Sg, Bh, Hs).

In some cases, the cathode active material may be doped with one or moredopants to alter the electrical properties (e.g., electricalconductivity) of the cathode active material. Non-limiting examples ofsuitable dopants include aluminum, niobium, silver, and zirconium.

In some embodiments, the cathode active material may be modified by asurface coating comprising an oxide. Non-limiting examples of surfaceoxide coating materials include: MgO, Al₂O₃, SiO2, TiO₂, ZnO₂, SnO₂, andZrO₂. In some embodiments, such coatings may prevent direct contactbetween the cathode active material and the electrolyte, therebysuppressing side reactions.

In certain embodiments, the cathode active material comprises sulfur. Insome embodiments, the cathode active material comprises electroactivesulfur-containing materials. “Electroactive sulfur-containingmaterials,” as used herein, refers to electrode active materials whichcomprise the element sulfur in any form, wherein the electrochemicalactivity involves the oxidation or reduction of sulfur atoms ormoieties. As an example, the electroactive sulfur-containing materialmay comprise elemental sulfur (e.g., S₈). In some embodiments, theelectroactive sulfur-containing material comprises a mixture ofelemental sulfur and a sulfur-containing polymer. Thus, suitableelectroactive sulfur-containing materials may include, but are notlimited to, elemental sulfur, sulfides or polysulfides (e.g., of alkalimetals) which may be organic or inorganic, and organic materialscomprising sulfur atoms and carbon atoms, which may or may not bepolymeric. Suitable organic materials include, but are not limited to,those further comprising heteroatoms, conductive polymer segments,composites, and conductive polymers. In some embodiments, anelectroactive sulfur-containing material within an electrode (e.g., acathode) comprises at least 40 wt % sulfur. In some cases, theelectroactive sulfur-containing material comprises at least 50 wt %, atleast 75 wt %, or at least 90 wt % sulfur.

Examples of sulfur-containing polymers include those described in: U.S.Pat. Nos. 5,601,947 and 5,690,702 to Skotheim et al.; U.S. Pat. Nos.5,529,860 and 6,117,590 to Skotheim et al.; U.S. Pat. No. 6,201,100issued Mar. 13, 2001, to Gorkovenko et al., and PCT Publication No. WO99/33130, each of which is incorporated herein by reference in itsentirety for all purposes. Other suitable electroactivesulfur-containing materials comprising polysulfide linkages aredescribed in U.S. Pat. No. 5,441,831 to Skotheim et al.; U.S. Pat. No.4,664,991 to Perichaud et al., and in U.S. Pat. Nos. 5,723,230,5,783,330, 5,792,575 and 5,882,819 to Naoi et al., each of which isincorporated herein by reference in its entirety for all purposes. Stillfurther examples of electroactive sulfur-containing materials includethose comprising disulfide groups as described, for example in, U.S.Pat. No. 4,739,018 to Armand et al.; U.S. Pat. Nos. 4,833,048 and4,917,974, both to De Jonghe et al.; U.S. Pat. Nos. 5,162,175 and5,516,598, both to Visco et al.; and U.S. Pat. No. 5,324,599 to Oyama etal., each of which is incorporated herein by reference in its entiretyfor all purposes.

One or more electrodes may further comprise additional additives, suchas conductive additives, binders, etc., as described in U.S. Pat. No.9,034,421 to Mikhaylik et al.; and U.S. Patent Application PublicationNo. 2013/0316072, each of which is incorporated herein by reference inits entirety for all purposes.

In some embodiments, the electrochemical cells of the battery furthercomprise a separator between two electrode portions (e.g., an anodeportion and a cathode portion). The separator may be a solidnon-conductive or insulative material, which separates or insulates theanode and the cathode from each other preventing short circuiting, andwhich permits the transport of ions between the anode and the cathode.In some embodiments, the porous separator may be permeable to theelectrolyte.

The pores of the separator may be partially or substantially filled withelectrolyte. Separators may be supplied as porous free standing filmswhich are interleaved with the anodes and the cathodes during thefabrication of cells. Alternatively, the porous separator layer may beapplied directly to the surface of one of the electrodes, for example,as described in PCT Publication No. WO 99/33125 to Carlson et al. and inU.S. Pat. No. 5,194,341 to Bagley et al.

A variety of separator materials are known in the art. Examples ofsuitable solid porous separator materials include, but are not limitedto, polyolefins, such as, for example, polyethylenes (e.g., SETELA™ madeby Tonen Chemical Corp) and polypropylenes, glass fiber filter papers,and ceramic materials. For example, in some embodiments, the separatorcomprises a microporous polyethylene film. Further examples ofseparators and separator materials suitable for use in this inventionare those comprising a microporous xerogel layer, for example, amicroporous pseudo-boehmite layer, which may be provided either as afree standing film or by a direct coating application on one of theelectrodes, as described in U.S. Pat. Nos. 6,153,337 and 6,306,545 byCarlson et al. of the common assignee. Solid electrolytes and gelelectrolytes may also function as a separator in addition to theirelectrolyte function.

As described above, in some embodiments, a force, or forces, is appliedto portions of an electrochemical cell. Such application of force mayreduce irregularity or roughening of an electrode surface of the cell(e.g., when lithium metal or lithium alloy anodes are employed), therebyimproving performance. Electrochemical devices in which anisotropicforces are applied and methods for applying such forces are described,for example, in U.S. Pat. No. 9,105,938, issued Aug. 11, 2015, publishedas U.S. Patent Publication No. 2010/0035128 on Feb. 11, 2010, andentitled “Application of Force in Electrochemical Cells,” which isincorporated herein by reference in its entirety for all purposes.

In the embodiments described herein, batteries may undergo acharge/discharge cycle involving deposition of metal (e.g., lithiummetal or other active material) on a surface of an anode upon chargingand reaction of the metal on the anode surface, wherein the metaldiffuses from the anode surface, upon discharging. The uniformity withwhich the metal is deposited on the anode may affect cell performance.For example, when lithium metal is removed from and/or redeposited on ananode, it may, in some cases, result in an uneven surface. For example,upon redeposition it may deposit unevenly forming a rough surface. Theroughened surface may increase the amount of lithium metal available forundesired chemical reactions which may result in decreased cyclinglifetime and/or poor cell performance. The application of force to theelectrochemical device has been found, in accordance with certainembodiments described herein, to reduce such behavior and to improve thecycling lifetime and/or performance of the cell.

In some embodiments, the battery (e.g., a housing of the battery) isconfigured to apply, during at least one period of time during chargeand/or discharge of the device, an anisotropic force with a componentnormal to an electrode active surface of one of the electrochemicalcells (e.g., first electrochemical cell, second electrochemical cell).

In some embodiments, an anisotropic force with a component normal to anelectrode active surface of one of the electrochemical cells (e.g.,first electrochemical cell, second electrochemical cell) is appliedduring at least one period of time during charge and/or discharge of thebattery. In some embodiments, the force may be applied continuously,over one period of time, or over multiple periods of time that may varyin duration and/or frequency. The anisotropic force may be applied, insome cases, at one or more pre-determined locations, optionallydistributed over an active surface of the one or more of theelectrochemical cells of the battery. In some embodiments, theanisotropic force is applied uniformly over one or more active surfacesof the anode.

An “anisotropic force” is given its ordinary meaning in the art andmeans a force that is not equal in all directions. A force equal in alldirections is, for example, internal pressure of a fluid or materialwithin the fluid or material, such as internal gas pressure of anobject. Examples of forces not equal in all directions include forcesdirected in a particular direction, such as the force on a table appliedby an object on the table via gravity. Another example of an anisotropicforce includes certain forces applied by a band arranged around aperimeter of an object. For example, a rubber band or turnbuckle canapply forces around a perimeter of an object around which it is wrapped.However, the band may not apply any direct force on any part of theexterior surface of the object not in contact with the band. Inaddition, when the band is expanded along a first axis to a greaterextent than a second axis, the band can apply a larger force in thedirection parallel to the first axis than the force applied parallel tothe second axis.

A force with a “component normal” to a surface, for example an activesurface of an electrode such as a anode, is given its ordinary meaningas would be understood by those of ordinary skill in the art andincludes, for example, a force which, at least in part, exerts itself ina direction substantially perpendicular to the surface. Those ofordinary skill can understand other examples of these terms, especiallyas applied within the description of this document.

In some embodiments, the anisotropic force can be applied such that themagnitude of the force is substantially equal in all directions within aplane defining a cross-section of the battery, but the magnitude of theforces in out-of-plane directions is substantially unequal to themagnitudes of the in-plane forces.

In one set of embodiments, batteries (e.g., housings) described hereinare configured to apply, during at least one period of time duringcharge and/or discharge of the cell, an anisotropic force with acomponent normal to an electrode active surface of one of theelectrochemical cells (e.g., first electrochemical cell, secondelectrochemical cell). Those of ordinary skill in the art willunderstand the meaning of this. In such an arrangement, theelectrochemical cell may be formed as part of a container which appliessuch a force by virtue of a “load” applied during or after assembly ofthe cell, or applied during use of the battery as a result of expansionand/or contraction of one or more components of the battery itself.

The magnitude of the applied force is, in some embodiments, large enoughto enhance the performance of the battery. An electrode active surface(e.g., anode active surface) and the anisotropic force may be, in someinstances, together selected such that the anisotropic force affectssurface morphology of the electrode active surface to inhibit increasein electrode active surface area through charge and discharge andwherein, in the absence of the anisotropic force but under otherwiseessentially identical conditions, the electrode active surface area isincreased to a greater extent through charge and discharge cycles.“Essentially identical conditions,” in this context, means conditionsthat are similar or identical other than the application and/ormagnitude of the force. For example, otherwise identical conditions maymean a battery that is identical, but where it is not constructed (e.g.,by couplings such as brackets or other connections) to apply theanisotropic force on the subject battery.

As described herein, in some embodiments, the surface of an anode can beenhanced during cycling (e.g., for lithium, the development of mossy ora rough surface of lithium may be reduced or eliminated) by applicationof an externally-applied (in some embodiments, uniaxial) pressure. Theexternally-applied pressure may, in some embodiments, be chosen to begreater than the yield stress of a material forming the anode. Forexample, for an anode comprising lithium, the cell may be under anexternally-applied anisotropic force with a component defining apressure of at least 10 kgf/cm², at least 20 kgf/cm², or more. This isbecause the yield stress of lithium is around 7-8 kgf/cm². Thus, atpressures (e.g., uniaxial pressures) greater than this value, mossy Li,or any surface roughness at all, may be reduced or suppressed. Thelithium surface roughness may mimic the surface that is pressing againstit. Accordingly, when cycling under at least about 10 kgf/cm², at leastabout 20 kgf/cm², and/or up 30 kgf/cm², up to 40 kgf/cm² ofexternally-applied pressure, the lithium surface may become smootherwith cycling when the pressing surface is smooth.

In some cases, one or more forces applied to the cell have a componentthat is not normal to an active surface of an anode. For example, inFIG. 1A force 184 is not normal to electrode active surfaces of thefirst electrochemical cell 110 and second electrochemical cell 120. Inone set of embodiments, the sum of the components of all appliedanisotropic forces in a direction normal to any electrode active surfaceof the battery is larger than any sum of components in a direction thatis non-normal to the electrode active surface. In some embodiments, thesum of the components of all applied anisotropic forces in a directionnormal to any electrode active surface of the battery is at least about5%, at least about 10%, at least about 20%, at least about 35%, at leastabout 50%, at least about 75%, at least about 90%, at least about 95%,at least about 99%, or at least about 99.9% larger than any sum ofcomponents in a direction that is parallel to the electrode activesurface.

In some cases, electrochemical cells may be pre-compressed before theyare inserted into housings, and, upon being inserted to the house, theymay expand to produce a net force on the electrochemical cells. Such anarrangement may be advantageous, for example, if the electrochemicalcells are capable of withstanding relatively high variations inpressure.

FIGS. 27A-27B show perspective view schematic illustrations of battery500, according to certain embodiments. Battery 500 shown in FIGS.27A-27B comprises a plurality of electrochemical cells arranged in stack550. FIG. 28 shows an exploded perspective view schematic illustrationof a repeating unit of components in battery 500 according to certainembodiments, comprising electrochemical cell 510 between first thermallyconductive solid article portion 531 and second thermally conductivesolid article portion 532 (shown as aluminum cooling fins with locatingholes and locating slots for alignment) and thermally insulatingcompressible solid article portion 540 shown as a compression foamcomprising microcellular elastomeric foam. Battery 500 in FIGS. 27A-27Balso comprises carbon fiber endplates 501 and 503 connected bycompression rods 505. Exemplary battery 500 can also include a power busand battery management system 580, as shown on the top of battery 500 inFIG. 27A. The electrochemical cells may comprise lithium metal anodes(e.g., vapor-deposited lithium metal) and lithium metal oxideintercalation cathodes (e.g., nickel-cobalt manganese intercalationcathodes).

FIGS. 29A-29E show schematic diagrams of components of exemplary battery500. FIG. 29A shows side view (center of FIG. 29A) and end view (rightside of FIG. 29A) schematic illustrations of battery 500, including aninset (left side of FIG. 29A). FIG. 29A depicts arrangements of endplate501, electrochemical cell 510 between first thermally conductive solidarticle portion 531 and second thermally conductive solid articleportion 532 (shown as aluminum cooling fins with locating holes andlocating slots for alignment) and thermally insulating compressiblesolid article portion 540 shown as a compression foam comprisingmicrocellular elastomeric foam. FIG. 29B shows an exploded schematicillustration (top) and a perspective view schematic illustration(bottom) of battery 500, according to certain embodiments, including asolid plate in the form of endplate 501, a coupling comprisingcompression rods 505, electrochemical cell 510, and thermally conductivesolid article portion 531). FIG. 29C shows schematic illustrations ofexemplary thermally conductive solid article portion 531 in the form ofa metal cooling fin comprising alignment feature 537 in the form of aholes and non-planarity 561 in the formed of a recessed pocket to coupleto the electrochemical cells (e.g., electrochemical cell 510). FIG. 29Dshows schematic illustrations of exemplary thermally insulatingcompressible solid article portion 540 in the form of a microcellularelastomeric foam. FIG. 29E shows schematic illustrations of exemplaryendplate 501 to be used in the housing of exemplary battery 500,endplate 501 being in the form of a laminate carbon fiber endplate,according to certain embodiments.

The following applications are incorporated herein by reference, intheir entirety, for all purposes: U.S. Patent Publication No. US2007/0221265, published on Sep. 27, 2007, filed as application Ser. No.11/400,781 on Apr. 6, 2006, and entitled “Rechargeable Lithium/Water,Lithium/Air Batteries”; U.S. Patent Publication No. US 2009/0035646,published on Feb. 5, 2009, filed as application Ser. No. 11/888,339 onJul. 31, 2007, and entitled “Swelling Inhibition in Batteries”; U.S.Patent Publication No. US 2010/0129699, published on May 17, 2010, filedas application Ser. No. 12/312,674 on Feb. 2, 2010, patented as U.S.Pat. No. 8,617,748 on Dec. 31, 2013, and entitled “Separation ofElectrolytes”; U.S. Patent Publication No. US 2010/0291442, published onNov. 18, 2010, filed as application Ser. No. 12/682,011 on Jul. 30,2010, patented as U.S. Pat. No. 8,871,387 on Oct. 28, 2014, and entitled“Primer for Battery Electrode”; U.S. Patent Publication No. US2009/0200986, published on Aug. 31, 2009, filed as application Ser. No.12/069,335 on Feb. 8, 2008, patented as U.S. Pat. No. 8,264,205 on Sep.11, 2012, and entitled “Circuit for Charge and/or Discharge Protectionin an Energy-Storage Device”; U.S. Patent Publication No. US2007/0224502, published on Sep. 27, 2007, filed as application Ser. No.11/400,025 on Apr. 6, 2006, patented as U.S. Pat. No. 7,771,870 on Aug.10, 2010, and entitled “Electrode Protection in Both Aqueous andNon-Aqueous Electrochemical cells, Including Rechargeable LithiumBatteries”; U.S. Patent Publication No. US 2008/0318128, published onDec. 25, 2008, filed as application Ser. No. 11/821,576 on Jun. 22,2007, and entitled “Lithium Alloy/Sulfur Batteries”; U.S. PatentPublication No. US 2002/0055040, published on May 9, 2002, filed asapplication Ser. No. 09/795,915 on Feb. 27, 2001, patented as U.S. Pat.No. 7,939,198 on May 10, 2011, and entitled “Novel Composite Cathodes,Electrochemical Cells Comprising Novel Composite Cathodes, and Processesfor Fabricating Same”; U.S. Patent Publication No. US 2006/0238203,published on Oct. 26, 2006, filed as application Ser. No. 11/111,262 onApr. 20, 2005, patented as U.S. Pat. No. 7,688,075 on Mar. 30, 2010, andentitled “Lithium Sulfur Rechargeable Battery Fuel Gauge Systems andMethods”; U.S. Patent Publication No. US 2008/0187663, published on Aug.7, 2008, filed as application Ser. No. 11/728,197 on Mar. 23, 2007,patented as U.S. Pat. No. 8,084,102 on Dec. 27, 2011, and entitled“Methods for Co-Flash Evaporation of Polymerizable Monomers andNon-Polymerizable Carrier Solvent/Salt Mixtures/Solutions”; U.S. PatentPublication No. US 2011/0006738, published on Jan. 13, 2011, filed asapplication Ser. 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U.S. Provisional Patent Application Ser. No. 62/937,761, filed Nov. 19,2019, and entitled “Batteries, and Associated Systems and Methods,” U.S.Provisional Application Ser. No. 62/951,086, filed Dec. 20, 2019, andentitled “Batteries, and Associated Systems and Methods,” U.S.Provisional Application Ser. No. 62/951,099, filed Dec. 20, 2019, andentitled “Electrochemical Cell Stacks, and Associated Components,” U.S.Provisional Application Ser. No. 62/951,144, filed Dec. 20, 2019, andentitled “Thermally Insulating Compressible Components for BatteryPacks,” U.S. Provisional Application Ser. No. 62/951,151, filed Dec. 20,2019, and entitled “Battery Alignment, and Associated Systems andMethods,” and U.S. Provisional Application Ser. No. 62/951,161, filedDec. 20, 2019, and entitled “Batteries with Components Including CarbonFiber, and Associated Systems and Methods,” are each incorporated hereinby reference in its entirety for all purposes.

It should be understood that when a portion (e.g., layer, structure,region) is “on”, “adjacent”, “above”, “over”, “overlying”, or “supportedby” another portion, it can be directly on the portion, or anintervening portion (e.g., layer, structure, region) also may bepresent. Similarly, when a portion is “below” or “underneath” anotherportion, it can be directly below the portion, or an intervening portion(e.g., layer, structure, region) also may be present. A portion that is“directly on”, “directly adjacent”, “immediately adjacent”, “in directcontact with”, or “directly supported by” another portion means that nointervening portion is present. It should also be understood that when aportion is referred to as being “on”, “above”, “adjacent”, “over”,“overlying”, “in contact with”, “below”, or “supported by” anotherportion, it may cover the entire portion or a part of the portion.

The following examples are intended to illustrate certain embodiments ofthe present invention, but do not exemplify the full scope of theinvention.

Example 1

This Example describes the measurement of electrochemical cellthicknesses and battery discharge capacity during the cycling of anexemplary battery. In the experiments, a uniform pressure of 12 kgf/cm²was applied to the electrochemical active areas of 20 Ah electrochemicalcells comprising lithium metal anodes. The pressure was applied to the91 mm×80 mm electrochemical active areas of the electrochemical cells.FIG. 30A shows a schematic illustration of the experimental apparatus,where a pneumatic cylinder press (Numatics Series NFPA, PN:F1AU-50AE-CAA3) equipped with a pressure regulator was employed to applypressure to the 20 Ah cell. The pneumatic cylinder was maintained at 80psi (12.28 kgf/cm²). A Tekscan 5101 sensor and I-scan software were usedto measure the pressure and pressure distribution. The sensor wascalibrated to a target pressure of 15 kgf/cm₂ with a 91 mm×80 mm area. AMitutoyo ABSOLUTE Digimatic Indicator (dial indicator) Model ID-C125EXBhaving a resolution of 0.00005 inches or 0.001 mm was used to measurethe height change during the application of pressure via the pneumaticcylinder press. The pressure sensor and the Mitutoyo Digimatic Indicatorwere connected to a laptop computer to record the data.

The testing procedure involved measuring and recording the initial 20 Ahelectrochemical cell thickness, and then assembling the 20 Ahelectrochemical cell and the Tekscan sensor 5101 between two 91 mm×80mm×6 mm pieces of Cellasto® elastomeric microcellular polyurethane foamlayers purchased from BASF in an interconnect tray assembly. The Tekscansensor was placed between the electrochemical cell and the Cellasto®foam. The assembly in the interconnect tray was placed in the cylinderpress assembly illustrated schematically in FIG. 30A, which was thenplaced in a containment box for fire safety. The Mitutoyo DigimaticIndicator was secured as shown in FIG. 30A.

One hundred thirty-two cycles were measured after three formationcycles, with each cycle consisting of a C/6 charge and a 2C/3 discharge.The formation cycles involved a 2 minute rest, followed by charging at1320 mA to 4.35 V (˜16 hours), tapering the charging at 4.35 V down to a264 mA current (˜15 minutes), followed by another 2 minute rest,followed by a discharge at 5280 mA to 3.2 V, with a capacity cut-off of15 Ah. The one hundred thirty-two post-formation cycles involved a 2minute rest, charging at 3300 mA to 4.35 V (˜6.6 hours), tapering thecharging at 4.35 V down to 660 mA (˜30 minutes), followed by a 2 minuterest, followed by discharging at 13,200 mA to 3.2 V, with a capacitycut-off of 15 Ah. The test ended after the one hundred thirty-two cycleswhen the cell capacity fell below the 15 Ah cut-off. Changes in thethickness of the cells were measured as displacement using the dialindicator. The electrochemical cell had a thickness of 8.110 mmfollowing the three formation cycles. FIG. 30B shows the results, withthe 0% state of charge (SOC) displacement shown as X's, the 100% SOCshown as boxes, the “breathing” shown as filled diamonds (the breathingbeing the difference between the 0% SOC and 100% SOC displacements), andthe discharge capacity of the battery shown as unfilled triangles. Thedata points were recorded at a rate of 1 per minute. Linear fits areshown as dashed lines.

As can be seen in FIG. 30B, an average breathing of the cells of 1.03 mmduring each cycle was observed, and an overall 0.6 mm growth of thecells from beginning of operational life (BoL) to end of operationallife (EoL) was observed during the course of the one hundred thirty-twocycles (comparing 0% SOC at BoL to 0% SOC at EoL).

Example 2

This Example describes the measurement of compression percentage of aseries of thermally insulating compressible solid articles as a functionof compressive stress. Each of the thermally insulating compressiblesolid articles was made of Cellasto® elastomeric microcellularpolyurethane foam purchased from BASF. Samples of varying uncompressedthickness and density were measured at different compression rates.

A total of 7 samples sets were used, each sample set having a quantityof 10 identical specimens measured under identical conditions, exceptfor sample set 7. Each specimen had a width and lateral dimensions of 91mm×80 mm. Compressive stress versus percent compression curves weregenerated by measuring foam displacement according to a modified versionthe ASTM D3574 standard test in which the compression rate was variedbetween different samples (specified in Table 1 below). Table 1 reportssample information:

TABLE 1 Sample set dimensions and properties. Uncompressed UncompressedSample Set No. Thickness (mm) Density (g/cm³) Compression Rate 1 3.150.45 0.1 mm/s 2 3.15 0.45 0.05 mm/s 3 6.35 0.45 0.1 mm/s 4 6.35 0.450.05 mm/s 5 6.35 0.6 0.1 mm/s 6 6.35 0.6 0.05 mm/s 7 6.35 0.6 6 hourduration

FIG. 31 shows the compressive stress versus percent compression curvesfor each of samples sets 1-7. The solids lines are the average measuredvalues for the specimens within the sample sets, and the dashed linesrepresent the first and third quartile as the statistical upper andlower limits. The measured curves showed that the mass density of thesamples had a significant effect on the stress-strain characteristics ofthe samples, with the more dense samples showing a more gradual andlower extent of compression than the less dense samples. The curvesshowed that the uncompressed thickness of the samples had a small butobservable effect on the extent of compression at lower compressivestresses and a more significant effect at high compressive stresses.During the experiments, it was observed that the Cellasto® foam sampleshad a continuous dynamic load limit of 40 kgf/cm². However, it was alsoobserved that single impacts generating compressive stresses of up to200 kgf/cm² did not cause failure of the samples.

The thick solid horizontal lines in FIG. 31 represent compressivestresses of 12 kgf/cm², 30 kgf/cm², and 40 kgf/cm². These lines indicatethat the thermally insulating compressible solid article samples testedin this Example are capable of undergoing compression of betweenapproximately 30% and approximately 50% under compressive stresses ofbetween 12 kgf/cm² and 30 kgf/cm².

Example 3

This Example describes displacement of exemplary endplates that can beincluded in a battery. Endplates with unidirectional carbon fiber withmoduli of 19 Msi (130 GPa), 33 Msi (226 GPa), and 53 Msi (363 GPa) and93 Msi (637 GPa) were used. The carbon fiber endplates had a laminatedesign (plies with a [0°/90°/0°] arrangement), and samples hadthicknesses of 8 mm, 10 mm, and 12 mm. FIG. 32A shows an illustration ofarrows indicating the direction of the application of force to thecarbon fiber end plates.

Sample plate 1 was a unidirectional carbon fiber end plate havingdimensions of 154 mm×84 mm×10 mm, a modulus of 33 Msi (226 GPa), a fibercontent of 65 wt %, a binder content of 35 wt %, a mass of 198 g, andhaving 51 laminated plies (layers) using a [0°/90°/0°] orientationsequence. A 9-point deflection test was simulated on sample plate 1using a force defining a uniform pressure of 12 kgf/cm² applied to a 91mm×80 mm area of the end plate. FIG. 32B shows a schematic of anine-point deflection test, which measured the displacement of thecarbon fiber end plate under a 12 kgf/cm² load. FIG. 32C shows side-viewschematic of an experimental setup for a 9-point deflection test as usedin examples below, indicating the direction of applied forces and theposition of deflection gauges. In this Example, finite element analysis(FEA) was used to analyze the deflection one would obtain in the setupof FIG. 32C. Table 2 shows a map of the raw data as well as the “delta”deflection difference with respect to the center point under the load.All values in Table 2 are in millimeters. For example, Table 2 showsthat plate 1 was deflected under the load by 0.488 more millimeters atpoint (1,1) than at the center point (2,2).

TABLE 2 9-Point Deflection Map for sample plate 1. 1 2 3 Raw (mm) 18.581 7.983 8.576 2 8.637 8.093 8.639 3 8.581 7.988 8.573 DeltaDeflection (mm) 1 0.488 −0.110 0.483 2 0.544 0.000 0.546 3 0.488 −0.1050.480

Sample plate 2 was a simulated unidirectional carbon fiber endplatehaving dimensions of 145 mm×84 mm×12 mm, a modulus of 93 Msi (637 GPa),a fiber content of 65 wt %, a binder content of 35 wt %, and having 63laminated plies (layers) using a [0°/90°/0°] orientation sequence.Uniform loads of 12 kgf/cm², 20 kgf/cm², and 40 kgf/cm² were applied tosample plate during FEA as conditions 2A, 2B, and 2C, respectively, anddeflection, Max Von Mises Stress, and safety factors were measured foreach condition. Table 3A shows lists condition information and thesimulated results from the load tests:

TABLE 3A Load measurements for sample plate 2. Values acquired fromsimulation. Load Max Von Condi- Condi- Deflection Mises tion Mass, tion,Max, Ideal, % devi- Stress. Safety No. grams kg/cm² mm mm ation MPaFactor 2A 217.72 12 0.06 0.1 −40 107.2 22.11 2B 217.72 20 0.11 0.1 10178.66 13.27 2C 217.72 40 0.22 0.1 120 357.38 6.63

Additionally, a 9-point deflection test was simulated for sample plate2, with a applied force defining a uniform pressure of 12 kgf/cm²applied to a 91 mm×80 mm area of the end plate. Table 3B shows a map theraw data for each of the 9 coordinates, as well as the “delta”deflection difference with respect to the center point (2,2) under theload. All values in Table 3B are in millimeters. For example, Table 3Bshows that sample plate 2 was deflected under the load by 0.103 moremillimeters at point (1,1) than at the center point (2,2).

TABLE 3B 9-Point Deflection Map for sample plate 2. Values acquired fromsimulation. 1 2 3 Raw (mm) 1 3.320 3.437 3.320 2 3.313 3.423 3.313 33.320 3.437 3.320 Delta Deflection (mm) 1 0.103 −0.014 0.103 2 0.1100.000 0.110 3 0.103 −0.014 0.103

Sample plate 3 was a simulated unidirectional carbon fiber endplatehaving dimensions of 145 mm×84 mm×10 mm, a modulus of 53 Msi (363 GPa),a fiber content of 65 wt %, a binder content of 35 wt %, and having 51laminated plies (layers) using a [0°/90°/0°] orientation sequence.Uniform loads of 12 kgf/cm², 20 kgf/cm², and 40 kgf/cm² were applied tosample plate 3 as conditions 3A, 3B, and 3C, respectively, anddeflection, Max Von Mises Stress, and safety factors were measured foreach condition. Table 4 shows lists condition information and thecalculations from the load tests:

TABLE 4 Load measurements for sample plate 3. Values acquired fromsimulation. Load Max Von Condi- Condi- Deflection Mises tion Mass, tion,Max, Ideal, % devi- Stress Safety No. grams kg/cm² mm mm ation MPaFactor 3A 181.24 12 0.187 0.1 210 153.96 15.39 3B 181.24 20 0.31 0.1 210256.94 9.22 3C 181.24 40 0.62 0.1 520 516.4 4.59

Comparison of the 9-point deflection maps for sample plate 1 and sampleplate 2 shows that the higher modulus of sample plate 2 compared tosample plate 1 contributes to smaller and more uniform deflections atall points in the two-dimensional array. Additionally, this data showsthat the carbon fiber plates described in this disclosure are capable ofundergoing max delta deflections of less than 0.4 mm under the loadstested, which may be useful in applications for which relatively uniformpressure distributions across electrochemical cell active regions aredesired.

Example 4

This Example describes pressure distribution and foam compressiondistribution measurements upon application of loads to unidirectionalcarbon fiber plates and thermally insulating compressible solidarticles. Sample plate 1 from Example 3 was used as the carbon fiber endplate. A 6.3 mm-thick (uncompressed) Cellasto® elastomeric microcellularpolyurethane foam purchased from BASF having dimensions of 95 mm×84mm×6.35 mm was used as the thermally insulating compressible solidarticle. Sample plate 1, the Cellasto® foam, and a 20 Ah electrochemicalcell (with a lithium metal anode) were arranged in a stack, with a 2 mmoffset between sample plate 1 and the Cellasto® foam. A uniform load wasapplied to the stack with the following statistics: average load=20.1kgf/cm², median load=20.9 kgf/cm², average deviation=3.65 kgf/cm²,standard deviation=4.24 kgf/cm², maximum load=30.6 kgf/cm², and minimumload=5.8 kgf/cm². Pressure measurements were made with a Tekscan 5101SN022 sensor integrated into the stack. The sensor had a calibratedtarget load of 20 kgf/cm² (based on a 5 point calibration), a calibratedmaximum load of 20.1 kgf/cm², and a sensitivity of S-22. Table 5 shows atwo-dimensional array of the load measurements from the Tekscan sensor.The array includes averaged measurements at locations of a 10×11 equallyspaced grid on the Tekscan scanner surface. The indices for the gridlocations are shown in bold font in Table 5.

TABLE 5 Two-dimensional array of pressure measurements (in kg_(f)/cm²).Index 0 1 2 3 4 5 6 7 8 9 10 0 14.3 15.3 15.3 15.1 15.3 15.3 16.0 15.817.0 17.5 16.5 1 15.8 18.6 19.1 19.4 19.0 19.5 20.8 20.4 21.3 21.6 19.12 17.1 21.9 22.3 23.1 23.1 22.6 23.7 22.7 24.1 24.3 20.3 3 17.4 22.623.6 24.5 24.4 24.5 24.7 25.0 25.3 24.8 21.7 4 18.3 23.4 24.3 24.8 25.224.4 25.6 24.7 25.8 26.6 23.9 5 17.0 21.8 24.0 24.9 25.0 24.7 24.8 24.125.8 25.3 22.7 6 16.6 20.2 21.8 23.5 24.4 22.8 23.8 23.4 24.1 24.7 21.57 15.4 19.4 20.9 23.0 23.8 22.6 23.1 22.5 22.8 23.6 20.7 8 13.6 16.418.8 19.8 19.6 19.8 19.9 20.4 21.0 20.7 18.4 9 11.7 13.8 15.5 15.7 15.515.4 16.2 15.7 16.2 15.3 14.4The measurements shown in Table 5 are indicative of the pressuredistribution across the face of components of the stack when pressure isapplied via the sample plate 1, with greater pressure experienced nearthe center and lower pressures experienced near the edges.

The spatial distribution of the average Cellasto® foam compression wasalso measured. Table 6 shows Cellasto® foam compression for a 3×3measurement (each value being an average of a 3×3 grid of adjacent cellsin the Tekscan scanner at the indicated location). The tables show mapsof the raw data for each of the 9 coordinates, as well as the “delta”compression difference with respect to the center point (middle, center)under the load.

TABLE 6 Compressive Displacement of Foam from Carbon Fiber EndplateDeflection Left Center Right Raw Compressive Displacement (mm) Top 2.462.65 2.68 Middle 2.90 3.63 2.95 Bottom 1.86 2.44 1.85 Delta Compression(mm) Top −1.17 −0.99 −0.95 Middle −0.73 0.00 −0.68 Bottom −1.77 −1.19−1.79

Tables 5 and 6 show that Cellasto® foam is capable of at least 50%compression under the applied loads via the carbon fiber end plates,with uniformity of compression within 2 mm across the two-dimensionalarray. Additionally, these results show that the Cellasto® foam cancompress enough under the applied loads to compensate for changes ofthicknesses of electrochemical cells of over 1 mm during cycling (i.e.,cell “breathing”).

Example 5

This example describes displacement of exemplary endplates that can beincluded in a battery. In this example the behavior of exemplaryendplates—sample plate 4 and sample plate 5—with different laminatedesigns is compared. The experimental setup was identical to that ofExample 3. As in Example 3, FIG. 32A shows an illustration of arrowsindicating the direction of the application of force to the carbon fiberend plates. As in Example 3, FIG. 32B shows a schematic of a 9-pointdeflection test, which measured the displacement of the carbon fiber endplate under a 12 kgf/cm² load, a 20 kgf/cm² load, and a 30 kgf/cm² load.

Endplates were constructed with unidirectional carbon fiber with moduliof 33 Msi (226 GPa) and a thickness of 10 mm. Sample plate 4 was aunidirectional carbon fiber end plate having dimensions of 154 mm×84mm×10 mm and possessing a laminate structure pictured in FIG. 33A (51plies with a [0°/90°/0°] arrangement). Sample plate 5 was aunidirectional carbon fiber end plate having dimensions of 154 mm×84mm×10 mm and possessing a laminate structure pictured in FIG. 33B (50plies with a [0°/30°/0°/−30°/0°] arrangement). FIG. 34A illustrates thegeometry of sample plate 4 and sample plate 5.

Table 7 shows a map of the raw data as well as the “delta” deflectiondifference with respect to the center point under each load condition.All values in Table 7 are in millimeters. For example, Table 7 showsthat sample plate 4 was deflected under the load by 0.5926 moremillimeters at point (1,1) than at the center point (2,2) under anapplied 30 kgf/cm² load. Table 8 shows the percent difference (in rawdata as well as the “delta” deflection) between values reported forsample plate 4 and sample plate 5 under an applied load. For example,Table 8 shows that at point (1,1) sample plate 4 experienced a deltadeflection of 0.5926 mm and sample plate 5 experienced a deltadeflection of 0.2903 mm under an applied 30 kgf/cm² load. Therefore, thepercent difference in the delta deflection at point (1,1) is equal to(0.2903 mm-0.5926 mm)/0.5926 mm*100%, which reduces to −51%.

TABLE 7 Nine-point deflection test results for sample plate 4 and sampleplate 5 under different loads. Sample plate 4: Sample plate 5:[0°/90°/0°] × 17 [0°/30°/0°/−30°/0°] × 10 1 2 3 1 2 3 30 kg_(f)/cm² 30kg_(f)/cm² Raw Data (mm) 1 0.8069 1.3936 0.8135 1 0.9064 1.4368 0.868 20.7805 1.3995 0.7872 2 0.6716 1.1967 0.677 3 0.773 1.3715 0.7823 30.8022 1.3469 0.8454 Delta 1 0.5926 0.0059 0.586 1 0.2903 −0.2401 0.3287Deflection (mm) 2 0.619 0 0.6172 2 0.5251 0 0.5197 3 0.6265 0.028 0.81353 0.3945 −0.1502 0.3513 20 kg_(f)/cm² 20 kg_(f)/cm² Raw Data (mm) 10.5569 0.9489 0.564 1 0.6138 0.9771 0.5974 2 0.5296 0.9421 0.5354 20.4448 0.7923 0.4511 3 0.5263 0.9274 0.5352 3 0.548 0.9104 0.5727 Delta1 0.3852 −0.0068 0.3781 1 0.1785 −0.1848 0.1949 Deflection (mm) 2 0.41250 0.4067 2 0.3475 0 0.3412 3 0.4158 0.0147 0.4069 3 0.2443 −0.11810.2196 12 kg_(f)/cm² 12 kg_(f)/cm² Raw Data (mm) 1 0.3518 0.5249 0.35931 0.3766 0.5952 0.3708 2 0.3222 0.564 0.3259 2 0.2642 0.469 0.2699 30.3145 0.5484 0.3201 3 0.3388 0.5545 0.3528 Delta 1 0.2122 0.0391 0.20471 0.0924 −0.1262 0.0982 Deflection (mm) 2 0.2418 0 0.2381 2 0.2048 00.1991 3 0.2495 0.0156 0.2439 3 0.1302 −0.0855 0.1162

TABLE 8 Percent difference between sample plate 4 and sample plate 5. 12 3 1 2 3 30 kg_(f)/cm² Raw Data 1 12%   3% 7% Delta Deflection 1 −51%−4169%  −44% (% difference) 2 −14%  −14% −14%  (% difference) 2 −15%−15% 3 4%  −2% 8% 3 −37% −636% −43% 20 kg_(f)/cm² Raw Data 1 10%   3% 6%Delta Deflection 1 −54% 2618% −48% (% difference) 2 −16%  −16% −16%  (%difference) 2 −16% −16% 3 4%  −2% 7% 3 −41% −903% −46% 12 kg_(f)/cm² RawData 1 7%  13% 3% Delta Deflection 1 −56% −423% −52% (% difference) 2−18%  −17% −17%  (% difference) 2 −15% −16% 3 8%  1% 10%  3 −48% −648%−52%

Table 7 and 8 demonstrate that under all applied loads, the deltadeflection was reduced by at least 15% in every observed position ofsample plate 5, relative to sample plate 4. The maximum raw deflectionincreased in some cases, which is attributed to a layering sequencevariation and manufacturing quality difference. In applications in whicha uniform pressure distribution is desired, a reduction in deltadeflection, as demonstrated for sample 5, can be desirable.

FIG. 34B illustrates an alternative sample plate geometry, which wasemployed for sample plate 6. Sample plate 6 was a unidirectional carbonfiber end plate having a thickness through its center of mass of 10 mmand in-plane dimensions of 154 mm×84 mm, where the in-plane dimensionsare measured along the dashed lines indicated in FIG. 34B. Sample plate6 possessed a laminate structure pictured in FIG. 33A (51 plies with a[0°/90°/0°] arrangement). Deflection results for sample plate 6 arecompared with deflection results for sample plate 5 in Table 9 and Table10, which are arranged identically to Table 7 and Table 8, respectively.These results demonstrate that sample plate deflection also depends onplate geometry, since the percent difference in delta deflectionobserved in Table 10 differs from the percent difference in deltadeflection observed in Table 8.

TABLE 9 Nine-point deflection test results for sample plate 6 and sampleplate 5 under different loads. Sample plate 6: Sample plate 5:[0°/90°/0°] × 17 [0°/30°/0°/−30°/0°] × 10 1 2 3 1 2 3 30 kg_(f)/cm² 30kg_(f)/cm² Raw Data (mm) 1 0.741 1.2604 0.7479 1 0.9064 1.4368 0.868 20.7348 1.2623 0.7378 2 0.6716 1.1967 0.677 3 0.7261 1.2529 0.7278 30.8022 1.3469 0.8454 Delta 1 0.5181 −0.0094 0.5151 1 0.2903 −0.24010.3287 Deflection (mm) 2 0.5268 0 0.5251 2 0.5251 0 0.5197 3 1.25291.2529 1.2529 3 0.3945 −0.1502 0.3513 20 kg_(f)/cm² 20 kg_(f)/cm² RawData (mm) 1 0.5164 0.8652 0.5229 1 0.6138 0.9771 0.5974 2 0.5027 0.8580.5036 2 0.4448 0.7923 0.4511 3 0.5007 0.8528 0.5005 3 0.548 0.91040.5727 Delta 1 0.3416 −0.0072 0.3351 1 0.1785 −0.1848 0.1949 Deflection(mm) 2 0.3553 0 0.3544 2 0.3475 0 0.3412 3 0.3573 0.0052 0.3575 3 0.2443−0.1181 0.2196 12 kg_(f)/cm² 12 kg_(f)/cm² Raw Data (mm) 1 0.327 0.48550.3347 1 0.3766 0.5952 0.3708 2 0.3084 0.5179 0.309 2 0.2642 0.4690.2699 3 0.3049 0.5114 0.3032 3 0.3388 0.5545 0.3528 Delta 1 0.19090.0324 0.1832 1 0.0924 −0.1262 0.0982 Deflection (mm) 2 0.2095 0 0.20892 0.2048 0 0.1991 3 0.213 0.0065 0.2147 3 0.1302 −0.0855 0.1162

TABLE 10 Percent difference between sample plate 6 and sample plate 5. 12 3 1 2 3 30 kg_(f)/cm² Raw Data 1 22% 14% 16% Delta Deflection 1 −44%2454% −36% (% difference) 2 −9% −5% −8% (% difference) 2  0%  −1% 3 10% 8% 16% 3 −69% −112% −72% 20 kg_(f)/cm² Raw Data 1 19% 13% 14% DeltaDeflection 1 −48% 2467% −42% (% difference) 2 −12%  −8% −10%  (%difference) 2  −2%  −4% 3  9%  7% 14% 3 −32% −2371%  −39% 12 kg_(f)/cm²Raw Data 1 15% 23% 11% Delta Deflection 1 −52% −490% −46% (% difference)2 −14%  −9% −13%  (% difference) 2  −2%  −5% 3 11%  8% 16% 3 −39%−1415%  −46%

Example 6

This example describes the pressure distribution within exemplarysingle-cell batteries. In this example the behavior of exemplaryendplates—sample plate 5 as described above, and sample plate 7—withdifferent laminate designs is compared. Both exemplary single-cellbatteries contained two 3 mm-thick (uncompressed) Cellasto® elastomericmicrocellular polyurethane foam sheets. Sample plate 7 was aunidirectional carbon fiber end plate having dimensions of 154 mm×84mm×10 mm and possessing a laminate structure pictured in FIG. 33A (51plies with a [0°/90°/0°] arrangement). FIG. 34A illustrates the geometryof sample plate 7, which was rotated 180° in-plane from the orientationof sample plates 4 and 5 described above. The experimental setup wasidentical to that shown in Example 3. As in Example 3, FIG. 32A shows anillustration of arrows indicating the direction of the application offorce to the carbon fiber end plates. The pressure and pressuredistribution were measured by a Tekscan 5101 sensor, as in Example 1.

FIGS. 35A-35B show the pressure (in kgf/cm²) of sample plate 5 averagedacross rows (FIG. 35A) and across columns (FIG. 35B) of the Tekscan 5101sensor after 44 charge/discharge cycles of the cell, with a 0% SOC underan applied load of 20 kgf/cm². FIGS. 36A-36B show the pressure (inkgf/cm²) of sample plate 7 averaged across rows (FIG. 36A) and acrosscolumns (FIG. 36B) of the Tekscan 5101 sensor after 43 cycles with a 0%SOC under an applied load of 20 kgf/cm². As indicated by the figures,the pressure was more uniform for sample plate 5 under these conditions.FIGS. 37A-37B show the pressure (in kgf/cm²) of sample plate 5 averagedacross rows (FIG. 37A) and across columns (FIG. 37B) of the Tekscan 5101sensor after 70 cycles with a 0% SOC under an applied load of 20kgf/cm². FIGS. 38A-38B show the pressure (in kgf/cm²) of sample plate 7averaged across rows (FIG. 38A) and across columns (FIG. 38B) of theTekscan 5101 sensor after 70 cycles with a 0% SOC under an applied loadof 20 kgf/cm². As indicated by these figures, the pressure was moreuniform for sample plate 5 under these conditions.

FIGS. 39A-39B show the pressure (in kgf/cm²) of sample plate 5 averagedacross rows (FIG. 39A) and across columns (FIG. 39B) of the Tekscan 5101sensor after 44 cycles with a 100% SOC under an applied load of 20kgf/cm². FIGS. 40A-40B show the pressure (in kgf/cm²) of sample plate 7averaged across rows (FIG. 40A) and across columns (FIG. 40B) of theTekscan 5101 sensor after 43 cycles with a 100% SOC under an appliedload of 20 kgf/cm². As indicated by these figures, the pressure was moreuniform across columns and less uniform across rows for sample plate 5under these conditions. FIGS. 41A-41B show the pressure (in kgf/cm²) ofsample plate 5 averaged across rows (FIG. 41A) and across columns (FIG.41B) of the Tekscan 5101 sensor after 69 cycles with a 100% SOC under anapplied load of 20 kgf/cm². FIGS. 42A-42B show the pressure (in kgf/cm²)of sample plate 7 averaged across rows (FIG. 42A) and across columns(FIG. 42B) of the Tekscan 5101 sensor after 69 cycles with a 100% SOCunder an applied load of 20 kgf/cm². As indicated by these figures, thepressure was more uniform across columns and less uniform across rowsfor sample plate 5 under these conditions. These results do notnecessarily reflect the final number of cycles reached by each exemplarybattery before failure. In other experiments, similar cells undersimilar conditions were able to achieve 115+/−10 cycles before reachinga cycle limit.

These results demonstrate that for some embodiments, the pressuredistribution experienced by a cell in a battery depends, at least inpart, on solid plate laminate structure, because in some exemplaryembodiments, the pressure can be made more or less uniform throughincorporation of a different laminate structure.

Example 7

This example describes 9-point deflection experiments performed onexemplary single-cell batteries comprising endplates and two 3 mm-thickCellasto® elastomeric microcellular polyurethane foam sheets, used todetermine suitable proportions for contoured solid article portions, inaccordance with some embodiments. The experimental setup was identicalto that shown in Example 3. As in Example 3, FIG. 32A shows anillustration of arrows indicating the direction of the application offorce to the carbon fiber end plates. As in Example 3, FIG. 32B shows aschematic of a 9-point deflection test, which measured the displacementof the carbon fiber end plate under a 20 kgf/cm² load or a 30 kgf/cm²load. The observed deflections are reported in Table 11, and variablespossess the same meaning and interpretation described in Example 5.

TABLE 11 Raw data and delta deflections for exemplary batteriescontaining sample plates 8 or 9. 1 2 3 1 2 3 Sample plate 8, 20kg_(f)/cm² applied load Raw Data 1 0.409 0.747 0.406 Delta Deflection 10.356 0.018 0.359 (mm) 2 0.415 0.765 0.397 (mm) 2 0.350 0 0.368 3 0.3410.769 0.416 3 0.334 −0.004 0.349 Sample plate 8, 30 kg_(f)/cm² appliedload Raw Data 1 0.640 1.163 0.637 Delta Deflection 1 0.521 −0.003 0.524(mm) 2 0.626 1.161 0.609 (mm) 2 0.535 0 0.551 3 0.618 1.121 0.611 30.542 0.039 0.550 Sample plate 9, 20 kg_(f)/cm² applied load Raw Data 10.547 1.010 0.548 Delta Deflection 1 0.473 0.010 0.471 (mm) 2 0.5391.019 0.522 (mm) 2 0.480 0 0.498 3 0.545 0.983 0.535 3 0.474 0.036 0.484

In this example, 9-point deflection experiments were performed on threeexemplary batteries. Two types of exemplary endplates—sample plate 8 andsample plate 9—were used. These had the geometry illustrated in FIG.34A, possessing a laminate structure pictured in FIG. 33A (51 plies witha [0°/90°/0°] arrangement and a 33 Msi (226 GPa) modulus). Sample plate8 had a thickness of 10 mm. Sample plate 9, had a thickness of 8 mm.Sample plate 8 and sample plate 9 possessed the [0°/90°/0°] laminatestructure pictured in FIG. 33A, and had a 33 Msi (226 GPa) modulus. Thefirst deflection experiment was performed with an applied load of 20kgf/cm² on an exemplary battery comprising sample plate 8. The secondwas performed with an applied load of 30 kgf/cm² on an exemplary batterycomprising sample plate 8. The third was performed with an applied loadof 20 kgf/cm² on an exemplary battery comprising sample plate 9.

These results informed the design of exemplary contoured solid articleportions in the form of contoured shims made of a Nylon-12 carbon fibercomposite, and a contour geometry illustrated in FIG. 43 . Two types ofexemplary shims were identified, sample shim 1 and sample shim 2.Contoured shims were designed with an ultimate compression strength of67 MPa along the XZ axis and 92 MPa along the ZX axis, at a compressionrate of 0.050 in./min, with a compression modulus of 2.7 MPa along theXZ axis and 2.2 MPa along the ZX axis. Sample shim 1 had the geometryillustrated in FIG. 44A, which shows an overall plate thickness of 0.9mm with an additional thickness of 0.75 mm through the center of thecontour. Sample shim 2 had the geometry illustrated in FIG. 44B, whichshows an overall plate thickness of 1.2 mm with an additional thicknessof 1.16 mm through the center of the contour.

In these experiments, an exemplary contoured shim geometry wasdisclosed, and 9-point deflection experiments were used to selectembodiments of this shim suitable for some batteries. These resultsindicate that contoured shim geometries may be tailored to take intoaccount deflection characteristics of endplates, and in some cases canpromote behavior tending toward more uniform pressure distributionsexperienced by electrochemical cells in batteries.

Example 8

This example describes the measured pressure distribution within anexemplary single-cell battery containing a contoured shim and two, 3 mmCellasto® elastomeric microcellular polyurethane foam sheets. Theexemplary battery further incorporated sample plate 7 endplates(described in Example 6), and sample shim 2 (described in Example 7).The experimental setup was identical to that of Example 3. As in Example3, FIG. 32A shows an illustration of arrows indicating the direction ofthe application of force to the carbon fiber end plates. The pressureand pressure distribution were measured by a Tekscan 5101 sensor, as inExample 1.

FIGS. 45A-45B show the measured pressure (in kgf/cm²) averaged acrossrows (FIG. 45A) and across columns (FIG. 45B) of the Tekscan 5101 sensorafter 80 cycles with a 100% SOC under an applied load of 20 kgf/cm², inthe presence of a contoured shim. These figures may be compared withFIGS. 42A-42B (described in Example 6), which show identical plots foran exemplary battery that lacked a contoured shim, but was otherwiseidentical, collected after 70 cycles with a 100% SOC.

FIGS. 45A-45B are characterized by a substantially higher uniformity ofmeasured pressure than FIGS. 42A-42B, demonstrating that for at leastsome embodiments, incorporation of a contoured shim can have asignificant effect on the distribution of pressure under an appliedload.

Example 9

This example describes the control of the pressure distributionexperienced by exemplary single-cell batteries, and resulting effects oncycling durability. In this example, control over these properties wasachieved by controlling endplate design, foam sheet thickness, and thedesign and incorporation of contoured shims (of the type described inExample 7) into the batteries. The experimental setup for measuringdeflection and pressure was identical to that of Example 3. As inExample 3, FIG. 32A shows an illustration of arrows indicating thedirection of the application of force to the carbon fiber end plates. Asin Example 3, FIG. 32B shows a schematic of a nine-point deflectiontest, which measured the displacement of the carbon fiber end plateunder loads of between 12 kgf/cm² and 30 kgf/cm². The pressure andpressure distribution were measured by a Tekscan 5101 sensor, as inExample 1. For all experiments described, the charge-discharge rateswere identical for all exemplary batteries and follow protocols outlinedin Example 1 (C/6 charge and 2C/3 discharge, abbreviated below as C/6C-2C/3 D). In some cases, the number of charge-discharge cyclescompleted before discharge capacity fell below a threshold value(referred to as the “cycle limit”) varied significantly with the foamand laminate structure.

FIG. 46A illustrates the effect of endplate thickness, endplate type,and SOC on the pressure within an exemplary battery, as a function ofthe number of charge-discharge cycles performed. The exemplary batteryhad exemplary endplates comprising a [0°/90°/0°] laminate structure witha 10 mm thickness and a 33 Msi (226 GPa) modulus (unless otherwise notedin the figure). The exemplary endplates had cross-sections identical tothe cross-section illustrated in FIG. 34A, unless designated in thefigure with ‘Alt’, which indicates that the exemplary endplates used thealternative cross-section illustrated in FIG. 34B. The exemplarybatteries were placed under an applied load of 12 kgf/cm², and containedtwo 3 mm-thick (uncompressed) Cellasto® elastomeric microcellularpolyurethane foam sheets. Pressure experienced by cells within thebatteries was elevated for cells with a higher SOC, and was observed toincrease linearly with the number of charge-discharge cycles.

FIG. 46B is similar to FIG. 46A, except that it demonstrates thebehavior of exemplary batteries without Cellasto® elastomericmicrocellular polyurethane foam sheets. The same type of linear trendswas generally observed, but the slope of the lines tended to be steeper.These results indicate that the presence or absence of Cellasto®elastomeric microcellular polyurethane foam sheets, as well as thegeometry and mechanical properties of exemplary endplates, can affectthe experienced pressure of batteries during cycling.

FIGS. 47A-49B present measured pressure distributions within anexemplary battery comprising a lithium metal electrochemical cell, undervarious conditions. This battery comprised exemplary endplatescomprising a [0°/90°/0°] unidirectional carbon fiber laminate structurewith a 10 mm thickness and a 33 Msi (226 GPa) modulus. The batteryfurther comprised two 3 mm foam-thick (uncompressed) Cellasto®elastomeric microcellular polyurethane foam sheets on either side of thecell. The cell and foam sheets and were placed under an applied load of12 kgf/cm² via the endplates. FIGS. 47A-47B show the measured pressure(in kgf/cm²) of cells averaged across rows (FIG. 47A) and across columns(FIG. 47B) of the Tekscan 5101 sensor after 1 cycle with a 0% SOC. FIGS.48A-48B show the pressure (in kgf/cm²) of cells averaged across rows(FIG. 48A) and across columns (FIG. 48B) of the Tekscan 5101 sensorafter 3 cycles with a 100% SOC. FIGS. 49A-49B show the pressure (inkgf/cm²) of cells averaged across rows (FIG. 49A) and across columns(FIG. 49B) of the Tekscan 5101 sensor after 63 cycles—the cycle limit ofthe cell in this particular battery—with a 0% SOC. These figuresdemonstrate that the pressure magnitude and spatial distribution isaffected by the state of charge of the cell and the cycle number. It isbelieved that lithium deposition upon charging causes “breathing”(change in cell thickness), which leads to greater pressure magnitudesunder the fixed endplate configuration and less uniform pressure acrossthe “column” dimension in the Tekscan sensor (which is believed to beattributable to deflection in the endplates caused by the load-bearingauxiliary fasteners near edges of the endplates).

FIG. 50 illustrates the effect of foam sheet thickness and contouredshims on the discharge capacity of exemplary single-cell batteries, as afunction of the number of charge-discharge cycles performed. Theexemplary single-cell batteries were placed under an applied load of 12kgf/cm². The exemplary endplates of these batteries were identical tosample plate 4, described above, comprising a [0°/90°/0°] unidirectionalcarbon fiber laminate structure with a 10 mm thickness and a 33 Msi (226GPa) modulus. The exemplary single-cell batteries contained two foamsheets with sheet thicknesses in the range of 3 mm to 5.5 mm, and onebattery contained a contoured shim that modulated the pressuredistribution experienced by the cell of the exemplary battery. Anadditional exemplary battery was subjected to thermal testing (at 40°C.) with the microcellular foam but without collecting pressure data. Inthe absence of a shim, the cycle limit was lowest in the exemplarybattery with the 3 mm foam sheets. When a contoured shim was included inthe exemplary battery, the cycle limit increased substantially,exceeding the cycle limit of batteries with thicker foam sheets whichlacked shims.

FIG. 51 is similar to FIG. 50 , this time illustrating the effect oflaminate structure and contoured shims on the discharge capacity ofexemplary batteries, as a function of the number of charge-dischargecycles performed. The exemplary batteries had exemplary endplatescomprising a [0°/90°/0°] unidirectional carbon fiber laminate structurewith a 31 Msi (363 GPa) modulus and endplate thicknesses in the range of8-12 mm. The exemplary batteries were placed under an applied load of 12kgf/cm². The exemplary batteries comprised two foam sheets with a sheetthickness of 3 mm, 4.5 mm, or 5.5 mm, and additionally comprised onecooling fin. Two of the exemplary batteries comprised exemplaryendplates with a 10 mm thickness. Each of the exemplary batteriescontained one of two different contoured shims (shim 1 and shim 2) ofthe type illustrated in FIG. 43 . The exemplary batteries had differentcycle limits, demonstrating that the shape of the contour shim canaffect this property. The exemplary battery with an 8 mm thick endplateand the exemplary battery with a 12 mm thick endplate did not containcontoured shims. As demonstrated by the results in FIG. 51 and in Table12, these exemplary batteries had different cycle limits, demonstratingthat the thickness of the exemplary endplates can affect this property.

TABLE 12 Cycle limits for different battery constructions. Cycle PlateThickness Modulus Foam Rate Limit [0/90/0] × 17 10 mm 33Msi 3 mm × 2 C/6C-2C/3 D 63 [0/90/0] × 17 10 mm 33Msi 3 mm × 2 C/6 C-2C/3 D 123[0/30/0/−30/0] × 10      10 mm 33Msi 3 mm × 2 C/6 C-2C/3 D 119 [0/90/0]× 20 12 mm 33Msi 3 mm × 2 C/6 C-2C/3 D 123 [0/90/0] × 20 12 mm 33Msi 3mm × 2 C/6 C-2C/3 D 124 [0/90/0] × 13  8 mm 33Msi 3 mm × 2 C/6 C-2C/3 D122 [0/90/0] × 13  8 mm 53Msi 3 mm × 2 C/6 C-2C/3 D 131 [0/90/0] × 13  8mm 53Msi 3 mm × 2 C/6 C-2C/3 D 117 [0/90/0] × 17 10 mm 33Msi 4.5 mm × 2 C/6 C-2C/3 D 79 [0/90/0] × 17 10 mm 33Msi 5.5 mm × 2  C/6 C-2C/3 D 76

These results collectively demonstrate that both endplate thickness,foam sheet thickness, and the shape and inclusion of contoured shims canaffect the pressure experienced by exemplary cells under an appliedload, as well as their cycle limit.

Example 10

This example describes the effect of the incorporation of contouredshims and variable-density foams on the cycle limit of exemplarysingle-cell batteries. In this example, one of two sample platetypes—sample plate 4 (described in example 5) or sample plate 7(described in Example 6)—is used as the endplates for all batteries.When exemplary batteries comprised contoured shims, one of two exemplaryshim types—sample shim 1 and sample shim 2, described in Example 7—wasincorporated into the battery. All batteries containing contoured shimscontained two, 3 mm Cellasto® elastomeric microcellular polyurethanefoam sheets of uniform density.

Exemplary batteries without contoured shims contained two 5.5 mm-thickCellasto® elastomeric microcellular polyurethane foam sheets. Onecontained a 5.5 mm-thick Cellasto® elastomeric microcellularpolyurethane foam sheets of uniform density. Another comprised 5.5 mmCellasto® elastomeric microcellular polyurethane foam sheets of variabledensity of the type illustrated in FIG. 52A, containing 1 row of holes.Another contained 5.5 mm Cellasto® elastomeric microcellularpolyurethane foam sheets of variable density of the type illustrated inFIG. 52B, containing 2 rows of holes. In both cases, variable densitywas achieved by excavating a set of holes out of the sheet to modulatethe film's local stiffness. Batteries were cycled according to a C/6C-2C/3 D charge-discharge protocol.

Results are presented in Table 13. These results show that changes inthe contour of a contoured shim, as well as endplate geometry for cellswith identical shim contours, can affect the cycle limit of exemplarybatteries. Exemplary batteries that contained variable-density Cellasto®elastomeric microcellular polyurethane foam sheets showed improvement inthe cycle-limit when the density of the Cellasto® elastomericmicrocellular polyurethane foam sheets near the edges was decreased.More specifically, the Cellasto® elastomeric microcellular polyurethanefoam sheets with uniform density had the lowest cycle limit (100), whilethe Cellasto® elastomeric microcellular polyurethane foam sheetscontaining two rows of holes had the highest cycle limit (110).

TABLE 13 Cycle limits for different battery constructions. Sample SampleCycle plate shim Foam Rate Limit 4 2 3 mm × 2 C/6 C-2C/3 D 90 7 2 3 mm ×2 C/6 C-2C/3 D 112 7 1 3 mm × 2 C/6 C-2C/3 D 104 7 None 5.5 mm × 2(Uniform) C/6 C-2C/3 D 100 7 None 5.5 mm × 2 (1 Row) C/6 C-2C/3 D 105 7None 5.5 mm × 2 (2 Rows) C/6 C-2C/3 D 110

Example 11

This example describes the discharge capacity and pressure experiencedby cells within an exemplary battery comprising multiple electrochemicalcells aligned in series (referred to as a “multi-cell stack”). Thismulti-cell stack comprised three electrochemical cells and four 4.5mm-thick (uncompressed) Cellasto® elastomeric microcellular polyurethanefoam sheets—one placed between the first electrochemical cell and thesecond electrochemical cell, one placed between the secondelectrochemical cell and the third electrochemical cell, one placedbetween the first electrochemical cell and a first endplate, and oneplaced between the third electrochemical cell and a second endplate. Theendplates comprised a [0°/90°/0°] laminate structure with a 10 mmthickness and a 33 Msi (226 GPa) modulus. The battery further comprisedthermally conductive solid articles in the form of aluminum cooling finsto assist with thermal management and alignment of the cells. A balanceboard was used to sync and balance the cells in the battery during thetesting of this Example. FIGS. 53A-53B illustrates this architecturewith exemplary battery 500 and balancing board 600. FIG. 53A presents afront-view illustration of battery 500 and balance board 600 multi-cellstack, while FIG. 53B presents perspective view illustration of thebattery 500 and balance board 600. During measurements, the stack in thebattery incorporated a Tekscan 5101 sensor with a 95 mm×84 mm area tomeasure pressure and pressure distribution—properties computed usingI-scan software. The sensor was equilibrated at 100 psi and calibratedusing five points of pressure (10 kgf/cm², 20 kgf/cm², 30 kgf/cm², 40kgf/cm², and 50 kgf/cm²) after being pressure soaked for at least threedays to properly precondition the sensor to the load applied in thetest. A load of 13.9 kgf/cm² was applied to the stack.

A plurality of charge-discharge cycles, consisting of a C/4 charge and a1 C discharge, were performed on the multi-cell stack, and the pressurewas monitored using the Tekscan 5101 sensor. FIG. 54 presents themeasured pressure as a function of cycle number and SOC. Also includedis the “Delta Pressure”, the pressure difference between a 0% SOC and a100% SOC within a given cycle. Pressure and delta pressure both dependedlinearly on cycle number. FIG. 55 presents the discharge capacity of themulti-cell stack in the exemplary battery as a function of cycle number.This discharge capacity decreased slowly over time, but was not observedto reach a cycle limit (as defined in Example 6) during thisexperiment's limited number of cycles.

After the experiment, cells from the exemplary multi-cell stack of thebattery were disassembled for visual inspection. A small amount of gaswas observed during disassembly. The cells remained evenly wet withelectrolyte, and a thin, black powder was observed on theelectrochemical active region of the lithium electrode—however, almostall lithium was observed to be metallic, with only a small quantity ofdecomposition products. Utilization across the cells was very uniform.

This example illustrates the viability of multi-cell stacks underapplied loads greater than the yield stress of the anode-formingmaterial, and indicates that, using combinations of components presentedand arranged in accordance with this disclosure, pressure fromanisotropic applied force can be controlled in a fashion consistent withthe single-cell examples previously presented.

Example 12

As illustrated by previous examples, the incorporation of thermallyinsulating compressible solid article portions in the form of foamsheets into exemplary batteries may be related to their long-termperformance, including their cycle limit, as well as to their pressuredistribution. In some cases, these properties could exhibit timedependence, due to the time-dependence of creep and force-relaxationwithin polymeric foams. To demonstrate this, two experiments wereperformed. In the first, an exemplary sheet of 5.5 mm-thick(uncompressed) Cellasto® elastomeric microcellular polyurethane foam wasplaced under a constant compressive load of 12 kgf/cm² for 96 hours, andthe compressive displacement was measured. The results of thisexperiment are reported in FIG. 56A. In the second, an exemplary 12-cellstack containing 13 sheets of 5.5 mm Cellasto® elastomeric microcellularpolyurethane foam was compressed to a fixed thickness of 148.8 mm, andthe measured response force was recorded for a period of 120 hours. Inaddition, the measured response force was converted to units of pressurefor different regions of the stack, where the cross-sectional area waseither 91 mm×80 mm or 95 mm×84 mm. These pressures are each equal to themeasured force divided by their respective cross-sectional area. Theresults of this experiment are reported in FIG. 56B.

When the sheet of 5.5 mm Cellasto® elastomeric microcellularpolyurethane foam was placed under a constant compressive load of 12kgf/cm² for 96 hours, it reached an ultimate displacement of 1.96 mm.However, in standard stress-strain compression experiments, identicallayers of foam only reach an instantaneous compressive displacement ofabout 1.75 mm. Consequently, the compression set for this layer of foamas measured by this constant load technique—the difference between thefinal displacement and the instantaneous displacement under appliedload—was approximately 11.4%.

In the 12-cell stack, the response force initially decreased rapidly,then continued to decrease slowly to a final value of 6.83 kN. Thissubstantial decrease may have implications for the pressure distributionof the exemplary 12-cell stack, indicating that rapid changes in appliedload or in experienced pressure (due to the rate ofcharging/discharging) could produce responses from the foam which differfrom their behavior in steady state.

While several embodiments of the present invention have been describedand illustrated herein, those of ordinary skill in the art will readilyenvision a variety of other means and/or structures for performing thefunctions and/or obtaining the results and/or one or more of theadvantages described herein, and each of such variations and/ormodifications is deemed to be within the scope of the present invention.More generally, those skilled in the art will readily appreciate thatall parameters, dimensions, materials, and configurations describedherein are meant to be exemplary and that the actual parameters,dimensions, materials, and/or configurations will depend upon thespecific application or applications for which the teachings of thepresent invention is/are used. Those skilled in the art will recognize,or be able to ascertain using no more than routine experimentation, manyequivalents to the specific embodiments of the invention describedherein. It is, therefore, to be understood that the foregoingembodiments are presented by way of example only and that, within thescope of the appended claims and equivalents thereto, the invention maybe practiced otherwise than as specifically described and claimed. Thepresent invention is directed to each individual feature, system,article, material, and/or method described herein. In addition, anycombination of two or more such features, systems, articles, materials,and/or methods, if such features, systems, articles, materials, and/ormethods are not mutually inconsistent, is included within the scope ofthe present invention.

The indefinite articles “a” and “an,” as used herein in thespecification and in the claims, unless clearly indicated to thecontrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in theclaims, should be understood to mean “either or both” of the elements soconjoined, i.e., elements that are conjunctively present in some casesand disjunctively present in other cases. Other elements may optionallybe present other than the elements specifically identified by the“and/or” clause, whether related or unrelated to those elementsspecifically identified unless clearly indicated to the contrary. Thus,as a non-limiting example, a reference to “A and/or B,” when used inconjunction with open-ended language such as “comprising” can refer, inone embodiment, to A without B (optionally including elements other thanB); in another embodiment, to B without A (optionally including elementsother than A); in yet another embodiment, to both A and B (optionallyincluding other elements); etc.

As used herein in the specification and in the claims, “or” should beunderstood to have the same meaning as “and/or” as defined above. Forexample, when separating items in a list, “or” or “and/or” shall beinterpreted as being inclusive, i.e., the inclusion of at least one, butalso including more than one, of a number or list of elements, and,optionally, additional unlisted items. Only terms clearly indicated tothe contrary, such as “only one of” or “exactly one of,” or, when usedin the claims, “consisting of,” will refer to the inclusion of exactlyone element of a number or list of elements. In general, the term “or”as used herein shall only be interpreted as indicating exclusivealternatives (i.e. “one or the other but not both”) when preceded byterms of exclusivity, such as “either,” “one of,” “only one of,” or“exactly one of.” “Consisting essentially of,” when used in the claims,shall have its ordinary meaning as used in the field of patent law.

As used herein in the specification and in the claims, the phrase “atleast one,” in reference to a list of one or more elements, should beunderstood to mean at least one element selected from any one or more ofthe elements in the list of elements, but not necessarily including atleast one of each and every element specifically listed within the listof elements and not excluding any combinations of elements in the listof elements. This definition also allows that elements may optionally bepresent other than the elements specifically identified within the listof elements to which the phrase “at least one” refers, whether relatedor unrelated to those elements specifically identified. Thus, as anon-limiting example, “at least one of A and B” (or, equivalently, “atleast one of A or B,” or, equivalently “at least one of A and/or B”) canrefer, in one embodiment, to at least one, optionally including morethan one, A, with no B present (and optionally including elements otherthan B); in another embodiment, to at least one, optionally includingmore than one, B, with no A present (and optionally including elementsother than A); in yet another embodiment, to at least one, optionallyincluding more than one, A, and at least one, optionally including morethan one, B (and optionally including other elements); etc.

In the claims, as well as in the specification above, all transitionalphrases such as “comprising,” “including,” “carrying,” “having,”“containing,” “involving,” “holding,” and the like are to be understoodto be open-ended, i.e., to mean including but not limited to. Only thetransitional phrases “consisting of” and “consisting essentially of”shall be closed or semi-closed transitional phrases, respectively, asset forth in the United States Patent Office Manual of Patent ExaminingProcedures, Section 2111.03.

What is claimed is:
 1. A battery, comprising: a stack comprising a firstelectrochemical cell and a second electrochemical cell, wherein: thefirst electrochemical cell comprises a first electrochemical activeregion having a largest dimension parallel to an exterior surface of thefirst electrochemical cell, and the second electrochemical cellcomprises a second electrochemical active region having a largestdimension parallel to an exterior surface of the second electrochemicalcell; and a housing at least partially enclosing the stack, the housingcomprising a solid plate covering at least a portion of an end of thestack; wherein: the housing is configured to apply, via the solid plateand tension in a solid housing component coupled to the solid plate,during at least one period of time during charge and/or discharge of thefirst electrochemical cell and/or the second electrochemical cell, ananisotropic force with a component normal to a first electrode activesurface of the first electrochemical cell and/or a second electrodeactive surface of the second electrochemical cell defining a pressure ofat least 10 kgf/cm²; the solid housing component comprises a metal,metal alloy, composite, polymeric material, or combination thereof; thesolid housing component comprises a tapered projection, the solid platecomprises a tapered recess complementary in shape to the taperedprojection, and the solid housing component and the solid plate areconfigured to form a joint at least in part via coupling of the taperedprojection and the tapered recess; and a ratio of the largest dimensionof the solid plate parallel to an exterior surface of the solid plate tothe largest dimension of the first electrochemical active regionparallel to an exterior surface of the first electrochemical cell and/ora ratio of the largest dimension of the solid plate parallel to anexterior surface of the solid plate to the largest dimension of thesecond electrochemical active region parallel to an exterior surface ofthe second electrochemical cell is less than or equal to 1.5.
 2. Abattery, comprising: a stack comprising a first electrochemical cell anda second electrochemical cell, wherein: the first electrochemical cellcomprises a first electrochemical active region having a largestdimension parallel to an exterior surface of the first electrochemicalcell, and the second electrochemical cell comprises a secondelectrochemical active region having a largest dimension parallel to anexterior surface of the second electrochemical cell; and a housing atleast partially enclosing the stack, the housing comprising a solidplate covering at least a portion of an end of the stack, wherein thehousing has a largest pressure applying dimension parallel to anexterior surface of the housing; wherein: the housing is configured toapply, via the solid plate and tension in a solid housing componentcoupled to the solid plate, during at least one period of time duringcharge and/or discharge of the first electrochemical cell and/or thesecond electrochemical cell, an anisotropic force with a componentnormal to a first electrode active surface of the first electrochemicalcell and/or a second electrode active surface of the secondelectrochemical cell defining a pressure of at least 10 kgf/cm²; thesolid housing component comprises a metal, metal alloy, composite,polymeric material, or combination thereof; the solid housing componentcomprises a tapered projection, the solid plate comprises a taperedrecess complementary in shape to the tapered projection, and the solidhousing component and the solid plate are configured to form a joint atleast in part via coupling of the tapered projection and the taperedrecess; and a ratio of the largest pressure-applying dimension of thehousing parallel to an exterior surface of the housing to the largestdimension of the first electrochemical active region parallel to anexterior surface of the first electrochemical cell and/or a ratio of thelargest pressure-applying dimension of the housing parallel to anexterior surface of the housing to the largest dimension of the secondelectrochemical active region parallel to an exterior surface of thesecond electrochemical cell is less than or equal to 1.6.
 3. The batteryof claim 2, wherein a ratio of the largest dimension of the solid plateparallel to an exterior surface of the solid plate to the largestdimension of the first electrochemical active region parallel to anexterior surface of the first electrochemical cell and/or a ratio of thelargest dimension of the solid plate parallel to an exterior surface ofthe solid plate to the largest dimension of the second electrochemicalactive region parallel to an exterior surface of the secondelectrochemical cell is less than or equal to 1.5.
 4. The battery ofclaim 1, wherein the end of the stack is a first end of the stack, thestack comprises a second end, and the solid housing component spans fromthe solid plate to the second end of the stack.
 5. The battery of claim1, wherein the solid housing component comprises a metal and/or metalalloy, and the metal and/or metal alloy comprises aluminum.
 6. Thebattery of claim 1, wherein the solid housing component comprises acomposite, and the composite comprises carbon fiber.
 7. The battery ofclaim 1, wherein the end of the stack is a first end of the stack, thesolid plate is a first solid plate, the stack further comprises a secondsolid plate covering at least a portion of a second end of the stack,and the second solid plate is coupled to the solid housing component. 8.The battery of claim 1, wherein the housing has a volume of less than orequal to 15000 cm³.
 9. The battery of claim 1, wherein the firstelectrochemical cell and/or the second electrochemical cell compriseslithium metal and/or a lithium metal alloy as an electrode activematerial.
 10. A method, comprising applying, to the battery of claim 1,an anisotropic force with a component normal to a first electrode activesurface of the first electrochemical cell and/or a second electrodeactive surface of the second electrochemical cell defining a pressure ofat least 10 kgf/cm².
 11. The battery of claim 6, wherein solid platecomprises carbon fiber.
 12. The battery of claim 7, wherein the taperedprojection is a first tapered projection, the tapered recess is a firsttapered recess, the solid housing component comprises a second taperedprojection, the second solid plate comprises a second tapered recesscomplementary in shape to the second tapered projection, and the solidhousing component and the second solid plate are configured to form ajoint at least in part via coupling of the second tapered projection andthe second tapered recess.
 13. The battery of claim 12, wherein thesolid housing component comprises carbon fiber, the first solid platecomprises carbon fiber, and the second solid plate comprises carbonfiber.
 14. The battery of claim 13, wherein the first electrochemicalcell and/or the second electrochemical cell comprises lithium metaland/or a lithium metal alloy as an electrode active material.
 15. Avehicle, comprising the battery of claim
 1. 16. The battery of claim 2,wherein the solid housing component and the solid plate each comprisescarbon fiber.
 17. The battery of claim 2, wherein the end of the stackis a first end of the stack, the solid plate is a first solid plate, thestack further comprises a second solid plate covering at least a portionof a second end of the stack, and the second solid plate is coupled tothe solid housing component.
 18. The battery of claim 17, wherein thetapered projection is a first tapered projection, the tapered recess isa first tapered recess, the solid housing component comprises a secondtapered projection, the second solid plate comprises a second taperedrecess complementary in shape to the second tapered projection, and thesolid housing component and the second solid plate are configured toform a joint at least in part via coupling of the second taperedprojection and the second tapered recess.
 19. The battery of claim 18,wherein the solid housing component comprises carbon fiber, the firstplate comprises carbon fiber, and the second solid plate comprisescarbon fiber.
 20. The battery of claim 2, wherein the firstelectrochemical cell and/or the second electrochemical cell compriseslithium metal and/or a lithium metal alloy as an electrode activematerial.
 21. A vehicle, comprising the battery of claim 2.